Which of the following relations is a function?
A.
(6, 11), (-8, 3), (0, 7), (0, -5)

B.
(0, 11), (-8, 3), (0, 7), (-8, -5)

C.
(11, 6), (3, -8), (7, 0), (11, -5)

D.
(6, 11), (-8, 3), (0, 7), (-5, 11)