Which set of ordered pairs does NOT represent a function?

{(8,9), (-2,9), (7,5), (-4, – 7)}

{(-5, -7),(-5,4), (-2,-8),(3,5)}

{(8,0),(-4, -2), (7,1),(0,0)}

{(-8,3), (-5, – 7),(-4,5), (9,3)}