IComparable (CompareTo takes one argument) and IComparer ( Compare takes two arguments)

Question

I was looking at the MSDN article
https://support.microsoft.com/en-us/kb/320727 on IComparable and IComparer. IComparable provides default sort order and IComparer provides custom sort order.
ICompareable interface requires that CompareTo method and takes one argument
IComparer interface requires that Compare method be implemented and takes two arguments
My question is : I can understand comparing two arguments, because we are comparing two objects / strings / int whatever the case be. But I don't understand IComparable Compare method which takes one argument, what is being compared with what? Below is the
code from the article.
int IComparable.CompareTo(object obj)
car c = (car)obj;
return String.Compare(this.make, c.make);
The this instance of the class is compared with the object obj based on the make. I guess I don't understand where are the two entries picked up from and in what order. Because this means the current instantiated class holding the current entry, then
what is the object? This is probably implementation detail on how the Sort works on the array. But I for some reason feel that the method with two arguments is intuitive as in IComparable Compare method

Answer 1

When there is a comparison job, it can be performed in two ways. You ask the object itself (i.e. the comparable) for the result. It then compares itself with the compared object and gives the result. Another way is to employ a judge. You give him the two
objects being compared together and ask him for the result.
When implementing IComparable<T> in a class, you want the class itself give you the result. The advantage of this approach is that, you don't need another object to compare the result as a judge. Comparison is done implicitly. However, the limitation
of this approach is that, you can implement the interface only once in a class.
The second approach has more flexibility, because you can change the judge and employ any judge as you want to give you the proper result. However, you need to create an instance of the IComparer<T> and use it explicitly to perform the comparison.