Which of the following relations describes a function?
OA. {(-2, 0), (0, -2), (0, 2), (2,0) }
OB. {(1,3), (1,4), (1,5), (1, 6) }
OC. {(2, 1), (3, 1), (4, 1), (5, 1) }
OD. {(0,0), (2,-2), (2, 2), (3, 3) }