Catch chose from list results, & use it

Question

The following script will activate/deactivate layers based on the letter {A, E, D, F} chosen from the list, then export single page (w 3 digits for the page number section) PDF. The problem I have I don't know to trap or cacth the results of whatever is chosen from the list & use it to name the pdf. If file name is ABC01_A_100.indd & the letter chosen from the list is "E" then final pdf should be ABC01_E_100.pdf.  If  the letter chosen from the list is D then final pdf is  ABC_D_100.pdf.  Basically what is changing whatever is between the two underscores _?_
I can see the results on the events window. How can I capture the results of whatever is chosen from list? I tried return statement but no success at all.
•Then the other question is  if i use choose from list with multiple selection allowed in which I can select more letters: A", "E", "D", "F" how can I output different PDFs with whatever is chosen from the list (with the correct layers activated/deactivated) & file names; ABC01_E_100.pdf, ABC01_F_100.pdf, ABC01_F_100.pdf.  See below. Please any input is greatly appreciated.
property myPDFpreset : missing value
set myPDFpreset to "Screen"
set versionLayers to {"A", "E", "D", "F"}
set the_choice to (choose from list versionLayers with prompt "What version do you need?" with multiple selections allowed) as text
set chosenVersionLayer to item 1 of the_choice
-->Activate versions Layers based in what was chosen
if the_choice is false then error number -128
if the_choice is "A" then
   myA()
else if the_choice is "E" then
   myE()
else if the_choice is "D" then
   myD()
else if the_choice is "F" then
   myF()
   end if
on myA()
   tell application "Adobe InDesign CS4"
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Search" to {visible:true}
           set properties of layer "Z1" to {visible:true}
           --Hide Layers
           set properties of layer "Z2" to {visible:false}
           set properties of layer "Z3" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
       end tell
       display alert " A activated"
   end tell
end myA
on myE()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Search" to {visible:true}
           set properties of layer "Z2" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z3" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
       end tell
       display alert " E activated"
        end tell
end myE
on myD()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Z3" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z2" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
           set properties of layer "Search" to {visible:false}
       end tell
       display alert "D activated" giving up after 6
        end tell
end myD
on myF()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Z3" to {visible:true}
           set properties of layer "NS" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z2" to {visible:false}
           set properties of layer "MD" to {visible:false}
           set properties of layer "Search" to {visible:false}
       end tell
       display alert "F activated" giving up after 6
    end tell
end myF
---======================
tell application "Adobe InDesign CS4"
   activate
   set source_folder to file path of active document --Put the PDFs same folder as ID file
   set theName to name of active document
   set text item delimiters of AppleScript to {"_"}
   set theShortName to text 1 thru text item -2 of theName
   --text 1 thru text item -2 is every character from the first character to the second to last text item
   set text item delimiters of AppleScript to ""
  tell application "Finder"
       if (exists folder "PDFs" of folder source_folder) is false then
           make folder at source_folder with properties {name:"PDFs"}
       end if
   end tell
   repeat with x from 1 to count pages of active document --single pages
       set thePageName to name of page x of active document
       set page range of PDF export preferences to thePageName
       --section-page number M-U-S-T have 3 digits
       set threeDigitPageName to text -3 thru -1 of ("00" & thePageName)
       (* text 1 thru 3 are the first 3 characters
                   text -3 thru -1 are the last 3 characters*)
       set theFilePath to source_folder & "PDFs:" & theShortName & "_" & threeDigitPageName & ".pdf" as string
----Export PDF as single pages
       tell active document
           export format PDF type to theFilePath using myPDFpreset without showing options
       end tell
end repeat
end tell

Answer 1

The following script will activate/deactivate layers based on the letter {A, E, D, F} chosen from the list, then export single page (w 3 digits for the page number section) PDF. The problem I have I don't know to trap or cacth the results of whatever is chosen from the list & use it to name the pdf. If file name is ABC01_A_100.indd & the letter chosen from the list is "E" then final pdf should be ABC01_E_100.pdf.  If  the letter chosen from the list is D then final pdf is  ABC_D_100.pdf.  Basically what is changing whatever is between the two underscores _?_
I can see the results on the events window. How can I capture the results of whatever is chosen from list? I tried return statement but no success at all.
•Then the other question is  if i use choose from list with multiple selection allowed in which I can select more letters: A", "E", "D", "F" how can I output different PDFs with whatever is chosen from the list (with the correct layers activated/deactivated) & file names; ABC01_E_100.pdf, ABC01_F_100.pdf, ABC01_F_100.pdf.  See below. Please any input is greatly appreciated.
property myPDFpreset : missing value
set myPDFpreset to "Screen"
set versionLayers to {"A", "E", "D", "F"}
set the_choice to (choose from list versionLayers with prompt "What version do you need?" with multiple selections allowed) as text
set chosenVersionLayer to item 1 of the_choice
-->Activate versions Layers based in what was chosen
if the_choice is false then error number -128
if the_choice is "A" then
   myA()
else if the_choice is "E" then
   myE()
else if the_choice is "D" then
   myD()
else if the_choice is "F" then
   myF()
   end if
on myA()
   tell application "Adobe InDesign CS4"
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Search" to {visible:true}
           set properties of layer "Z1" to {visible:true}
           --Hide Layers
           set properties of layer "Z2" to {visible:false}
           set properties of layer "Z3" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
       end tell
       display alert " A activated"
   end tell
end myA
on myE()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Search" to {visible:true}
           set properties of layer "Z2" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z3" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
       end tell
       display alert " E activated"
        end tell
end myE
on myD()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Z3" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z2" to {visible:false}
           set properties of layer "NS" to {visible:false}
           set properties of layer "MD" to {visible:false}
           set properties of layer "Search" to {visible:false}
       end tell
       display alert "D activated" giving up after 6
        end tell
end myD
on myF()
   tell application "Adobe InDesign CS4"
       --set myDocument to active document
       tell active document
           --Activate Layers
           set properties of layer "Tive" to {visible:true}
           set properties of layer "Logo" to {visible:true}
           set properties of layer "Z3" to {visible:true}
           set properties of layer "NS" to {visible:true}
           --Hide Layers
           set properties of layer "Z1" to {visible:false}
           set properties of layer "Z2" to {visible:false}
           set properties of layer "MD" to {visible:false}
           set properties of layer "Search" to {visible:false}
       end tell
       display alert "F activated" giving up after 6
    end tell
end myF
---======================
tell application "Adobe InDesign CS4"
   activate
   set source_folder to file path of active document --Put the PDFs same folder as ID file
   set theName to name of active document
   set text item delimiters of AppleScript to {"_"}
   set theShortName to text 1 thru text item -2 of theName
   --text 1 thru text item -2 is every character from the first character to the second to last text item
   set text item delimiters of AppleScript to ""
  tell application "Finder"
       if (exists folder "PDFs" of folder source_folder) is false then
           make folder at source_folder with properties {name:"PDFs"}
       end if
   end tell
   repeat with x from 1 to count pages of active document --single pages
       set thePageName to name of page x of active document
       set page range of PDF export preferences to thePageName
       --section-page number M-U-S-T have 3 digits
       set threeDigitPageName to text -3 thru -1 of ("00" & thePageName)
       (* text 1 thru 3 are the first 3 characters
                   text -3 thru -1 are the last 3 characters*)
       set theFilePath to source_folder & "PDFs:" & theShortName & "_" & threeDigitPageName & ".pdf" as string
----Export PDF as single pages
       tell active document
           export format PDF type to theFilePath using myPDFpreset without showing options
       end tell
end repeat
end tell