Sendo A= {3,4,5,6,7} e B = {5,6,7,8,9...}. marque a alternativa correta para: A U B:

a) {3,4,5,6,7,8,9...}
b) {1,2,3,4,5,6}
c) {0, 1,2,3,4,5,6,7,8}
d) {1,3,5,7,9...}​