Which set of ordered pairs represents a function?
O{(-1,-6), (-1, -2), (5, -1), (7,-2)}
O {(5,-9), (-2, -7), (5,4), (3,7)}
O {(4,-4), (-4,-4), (-7, -2), (-6,6)}
{(-4, 7), (-4, - 7), (-3,6), (-6, -6)}