Which of the following lists of ordered pairs is a function?
A. (1,1),(2,3)(1,5),(4,7)
B. (2,4),(-2,4), (3,9), (-2,-4)
C. (2,4), (3,9),(4,16), (5,25)
D. (0,2), (4,2), (0, -4), (4.-2)