请教MATH7-Q11

答案据说是A，请NN指教~谢谢啦

Q11:

If x is a positive integer, is the remainder 0 when 3^x + 1 is divided by 10?

(1)     x = 4n + 2, where n is a positive integer.

(2)     x > 4

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

3的n次方的个位呈3,9,7,1循环

(1)3的4n+2次幂,4n+2是4的倍数余2,故3^(4n+2)的个位是9, 3^x +1一定能被10整除

(2)无法判断

故选a