Question

Which sets of ordered pairs represent functions from A to B?

A = {1, 2, 3, 4) and B = {-2, -1, 0, 1, 2)

{(1, -1), (3, 2), (2, -2), (4, 0), (2, 1)) {(1, 2), (4, 0), (2, 1)) {(1, 1), (2, -2), (3, 0), (4, 2)} {(1, 0), (2, 0), (3, 0), (4, 0))