Oracle 1Z0-808 Exam question no. 9

Q - Given:-

interface I   {
        public void displayI ( ); 
}
abstract class C2 implements I   {
               public void displayC2 ( ) {
                       System.out.print ("C2");
               }
}
class C1 extends C2   {
              public void displayI ( )  {
                         System.out.print ("C1");
              }
}

And the code fragment:-

C2 obj1= new C1( );
I obj2 = new C1 ( );

C2 s= (C2) obj2 ;
I t = obj1;

t.displayI( );
s.displayC2( );

What is the result?

A) C2C2

B) C1C1

C) Compilation fails.

D) C1C2


⧪ please give your answer in a comment section.