SUPER EASY HELP ME
Which of the following relations is a function?
A.
(2, 0), (-5, 3), (5, 1), (-5, 5)

B.
(2, 4), (-5, 6), (2, 3), (-6, 2)

C.
(5, 1), (-5, 4), (2, 1), (5, 2)

D.
(2, 4), (-5, 2), (5, 1), (-6, 2)