which of the following relations shows a function? {(-5, 6), (4, -3), (2, -1), (4, 2)} {(3, -1), (3, -5), (3, 4), (3, 6)} {(-2, 3), (0, 3), (-2, -1), (-1, 2)} {(-5, 6), (-4, -3), (2, -1), (4, 2)}