Which set of ordered pairs does not represent a function?
A.{(-3,7), (-6, -6),(-2, -9), (-2,9)}
B. {(7,-5), (-9,-5),(-4,-8), (-2,-4)}
C. {(-8,-5), (0,–2),(-3, -2), (4,5)}
D.{(8,8), (7,9), (-3, -8),(4, -8)}