请教大家一个问题

ukiyo

Q11:

If n and k are positive integers, is n divisible by 6?

(1)     n = k(k + 1)(k - 1)

(2)     k – 1 is a multiple of 3.

                  

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.

答案是A，可是我觉得条件(2)也sufficient，因为k-1是3的倍数，也就是说k不是，那k就一定不能被6 整除，不是只要能够判断就行吗？