contestada

Which relation is a function?
OA.
{(2, 3), (1, 5), (2, 7))
B. (-1, 5), (-2, 6), (-3, 7)
Oc. (11,9), (11, 5), (9, 3))
OD.
(3, 8), (0, 8), (3, -2)}