Hi.....
I have a question & its answer but i am confuse about it.
If any one clear about thsi question explain me.

Question is

class class1{}
class class2 extends class1{}
class class3 extends class3{}


When is the following method valid?
public class1 castMe(class3 ref){
return (class1)ref;
}

A. Always
B. Never
C. If and only if ref references an class3 object
D. If and only if ref references an class2 object


Answer : A