Definition of a Function Which of the following sets of data represent valid functions? OR = {(0, -2), (3, 1), (4, 5), (7,9), (16, 15)} OG = {(-5, -1), (2, 1), (2, 6), (9, 7), (12, 16) } DS = {(-3, -4), (1, 3), (5, 6), (-3, -4), (12, 14) } OF = {(-1, -3), (3, 1), (6, 4), (9,7), (15, 11) }