Determina si los siguientes grafos corresponden a funciones. 2. ((1,0), (2,0), (3,0). (7, 0)) b. ((2, 1), (2,6), (2,5), (2,8)} c. [(13, 0), (4, 9), (5, 3), (2, 1)) d. ((a, 1), (b. 2), (c, 3), (d, 4))