What is the result?

Yes, A is correct, I tested with code

interface Contract{}
class Super implements Contract{};
class Sub extends Super{};

public class A106 {

public static void main(String[] args) {
// TODO Auto-generated method stub
List objs = new ArrayList();
Contract c1 = new Super();
Contract c2 = new Sub();
Super s1 = new Sub();

objs.add(c1);
objs.add(c2);
objs.add(s1);
for (Object object : objs) {
System.out.println(object.getClass().getName());
}
}

}