Which set of ordered pairs does not represent a function?
O {(-8,0), (-4,5), (-5,5), (-7,-5)}
O {(2,-9), (-9,-6), (4, -6), (3,6)}
O {(-4, 6), (-5, -1), (-1,-5), (2, 1)}
O {(-2,-8), (0, -7), (8, -3), (0, -5)}