Interface in java

Hello ! i m a beginner in java .Kindly help me to solve these questions
Which of the following statements will compile without error?
interface IFaca{}
class CFace implements IFace{}
class Base{}
public class ObRef extends Base{
        public static void main(String argv[]){
          ObRef ob = new ObRef();
          Base b   = new Base();
          Object o1= new Object();
          IFace o2 = new CFace();
A. o1=o2;
B. b=ob;
C. ob=b;
D. o1=b;
Options----
1. A,B,D
2. A,B,C
3. B,C,D
4. D,C,A

hi Payal,
In this case Option 1 is correct.
Please assign points if it is helpful.
Regards,
Richa.

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Interface in java

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