1. Determine whether the following statements are true or false.

If they are true to prove them if they are false to provide a counterexample.

(a) The difference between any two odd integers is even.

(b) If ???? and ???? are integers and ???? +???? is even, then either ???? is even or ???? is even.

(c) If ???? is odd and ???? is even, then ???? + ???? is odd.