PLEASE ANSWER BOTH QUESTIONS

1) Which set is a function?

A{(0,3), (3,0), (0,4), (4,0)}

B{(0,2), (2,0), (4,6), (6,4)}

C{(2,6), (3,6), (4,6), (2,0)}

D{(6,2), (2,0), (4,6), (6,4)}

2)Which set of ordered pairs does NOT represent a function?

A(0, 1), (2, 2), (4, 8), (-2, 7), (5, 8)

B(0, 1), (2, 2), (4, 8), (2, 7), (5, 8), (7, 9)

C(-3, 6), (2, 7), (0, 5), (1, 5), (4, 9), (5, 4)

D(-4, 2), (-3, 2), (-2, 2), (-1, 2), (0, 2), (1, 2)