Which set of ordered pairs does not represent a function? {(1, 10), (3, 18), (5, 26), (7, 34), (9, 42)} {(0, 8), (5, 4), (10, 0), (15, 4), (20, 8)} {(2, 10), (3, 20), (4, 15), (5, 5), (6, 25)} {(9, 1), (6, 2), (3, 3), (6, 4), (9, 5)}