If A = {5, 3, 6, 10, 12, 15, 13} and B = {12, 25, 21, 5, 13}, find A ∪ B.A. { }B. {5, 12, 13}C. {5, 3, 6, 9, 12, 15, 13}D. {3, 5, 6, 10, 12, 13, 15, 21, 25}