Which of the following relationships represents a function?
A. (-2,0), (5,3), (2,1), (5,5)
B. (-2,4), (5,6), (-2,3), (9,2)
C. (-2,4), (5,6), (5,3), (9,2)
D. (-2,4), (5,2), (2,1), (9,2)