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