請教各位前輩一個數學問題

assfgrtrtr

If 。represents one of the operations +,－, and ×, is k。(l+m)=(k。L)+(k。m) for all numbers k, l, m ?

(1) k。1 is not equal to 1。k for some numbers k.
(2) 。 represents subtraction.

Ans: D

I know the (2) is right, but why (1) is right.
Please tell me why?
Thanks!

lololo

由（1）可以推出（2），由（2）推出结论不成立，所以选D