Which of the following tables do NOT represent a function?

A. X 1 3 7 5 2 4
Y 3 3 3 3 3 3

B. X 9 4 2 5 6 4
Y 7 4 9 2 5 4

C. X 7 8 2 5 1 7
Y 7 5 9 2 5 3

D. X 1 3 2 5 6 4
Y 6 4 3 3 5 1

The table that does NOT represent a function is table B.