Java please

1) Method overloading

public int foo (int x, String y) {...}

Which of the following methods is NOT allowed to be defined in the same class A? Choose the letter in front of All that apply and please explain why you chose it.

a) public int foo(int x, int y) {...}

b) public int bar(int x, String y) {..}

c) public int foo(int x, String y, char z) {...}

d) public int foo(int a, String b) {...}

e) public int foo(int x) {...}

f ) public int foo(String y, inx x) {...}

2) Given this class:

public class Foo {

private int x;

public Foo(int arg) {x = arg; }

public void expand() { x = x + x; }

}

Create a child calss named bar, with a constructor assigning all fields, that overrides expand, causing it to quadruple x's value.