Which of the following relations is a function?
(A) {(-3, 1), (0, 1), (2,5)}
(B) {(2, -3), (2,0), (2,5)}
(C) {(-2,-2), (0, 0), (0, -2)}
(D) {(1, -3), (0, -1), (3, 2), (1, 0 )​