请教一道数学题和有关factor的概念

Q13:

An integer greater than 1 that is not prime is called composite.  If the two-digit integer n is greater than 20, is n composite?

(1)     The tens digit of n is a factor of the units digit of n.

(2)     The tens digit of n is 2.

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,我怎么觉得是c呢?

对于12来说, 1 和12 算不算12的factor呢? factor 不一定非要是质数吧?6也是12的factor吧?

谢谢大家

题目说，If the two-digit integer n is greater than 20, is n composite?

所以tens digit不是1。

只要unit digit是某数的倍数，而它又不是1，那么一定是composite.

所以选择A

原来是这样,大于20的条件原来这样用啊!

谢谢你!