Answer:
Step-by-step explanation:
(C). ASA postulate of congruence.
If N is a positive integer, it must be either even or odd.
If N is odd, then N-1 will be even.
If N is even, then N-1 will be odd.
Either way, when you multiply n and n-1, one of those expressions is going to be an even number, and any number multiplied by an even number is an even number.
Hope this helps! :)