单选题 If X and Y are sets of integers, X△Y denotes the set of integers that belong to set X or set Y, but not both. If X consists of 10 integers, Y consists of 18 integers，and 6 of the integers are in both X and Y, then X△Y consists of how many integers?
(A) 6 (B) 16 (C) 22
(D) 30 (E) 174