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