class One {
public One foo() { return this; }
}
class Two extends One {
public One foo() { return this; }
}
class Three extends Two {
// insert method here
}
Which two methods, inserted individually, correctly complete the Three class?()
A. public void foo() { }
B. public int foo() { return 3; }
C. public Two foo() { return this; }
D. public One foo() { return this; }
E. public Object foo() { return this; }