Bob purchased 18 cans of soda, some of which contained diet soda. How many of the cans did not contain diet soda?

(1) Of the cans Bob purchased, the number containing diet soda is equal to the number not containing diet soda.
(2) Of the cans Bob purchased, the number containing diet soda is odd

The OA is A.

What is the best way to write down this DS question. I don't know how can I say that statement (2) is not sufficient. Can any expert say to me how should I prove it?