Which set of ordered pairs does not represent a function?
{(5,–9), (6,-6), (-3,8), (9,-6)}
O{(-6,-4),(4, -8), (-6,9), (1, -3)
O {(1, -1),(-5,7),(4, -9), (-9,7)}
O {(8, –9), (-3, -6), (-4, 4), (1, -5)}