Which table represents y as a function of x?

A. xy
0 1
0 2
1 3
2 3

B. x---y
−1 −1
−1 0
0 2
2 3

C. x---y
−1 −1
0 −1
2 0
3 2

D. x---y
1 0
2 0
3 1
3 2