Which of the following constructor signatures must exist in the Demo class for DerivedDemo to compile correctly? : Questions « Object Oriented « SCJP

1. SCJP
2. Object Oriented
3. Questions

class Demo{

}

 public class DerivedDemo extends Demo{
   int M, N, L ;
   public DerivedDemo( int x, int y ){
     M = x ; N = y ;
   }
   public DerivedDemo( int x ){
     super( x );
   }
 }


A.      public Demo(int a, int b).
B.      public Demo(int c).
C.      public Demo().
D.      There is no requirement for a constructor in Demo.