In which choice is y a function of x?
A (-2, 3), (0, 2), (-1, 1), (0, 0)
B. (4, 1), (1, 4), (-4, 1), (1, 4)
C. (4, 1), (4, 2), (4,3), (4,4)
D. (0, 2), (1, 1), (3, 0), (0, -2)