单选题 If x is an integer, then the units digit of x squared cannot be

(A) 0
(B) 1
(C) 2
(D) 5
(E) 6

【正确答案】 C

【答案解析】To solve this problem, find examples of squares in which the units digit is equal to the answer choices in order to eliminate answers: 10²=100, so eliminate answer choice A; 1²=1 and 9²=81, SO eliminate answer choice B; 5²=25, so eliminate answer choice D; 6²=36, so eliminate answer choice E. There is no example that allows you to eliminate answer choice C, so it must be the correct answer.