Which set of ordered pairs represents a function?
{(-8, 1), (5. –7),(-6,9), (-6, -9)}
o{(-2,-3), (2, 1), (2,6), (4,9)}
o{(8,4), (6,4), (9,1),(7-6)}
o{(-4,5),(0,0), (2, -8), (2,0)}