13. Given a binary tree as follows, please indicate the result of pre-order traversal.(A) 7, 5, 28, 40, 36, 12, 79, 50, 49, 86, 96, 81, 99, 43(B) 5, 7, 12, 28, 36, 40, 43, 49, 50, 79, 81, 86, 96, 99(C) 43, 12, 5, 36, 7, 28, 40, 99, 81, 49, 96, 50, 86, 79(D) 43, 12, 99, 5, 36, 81, 7, 28, 40, 49, 96, 50, 86, 79(E) 43, 12, 5, 7, 36, 28, 40, 99, 81, 49, 50, 79, 96, 86