Which sets of ordered pairs represent a function? Select all that apply.
A {(3,5), (4, -1), (2, -1), (2, 7), (-3, 6)}
B {(-3, 9), (-2, 4), (-1, 1), (0, 0), (1, 1)}
C {(1, 1), (4, 2), (9, 3), (16, 4), (25, 5)}
D {(9, -3), (4, -2), (1, -1), (0, 0), (1, 1)}