Which set of ordered pairs does not represent a function?
O{(-3, -3), (6, -1), (4, -4), (9, -3)}
O{(-5,8), (4,3), (-4, -4), (2,8)}
O {(6, -1), (-2, -1), (-8, -4), (5,9)}
O {(4, -2), (1,9),(-1,2), (1,4)}