Concept: The question tests on the area of Number Properties
The product of 2 even numbers or the product of an even and an odd number is always even.
The product of 2 numbers can be odd only if both are odd.
Therefore m and n are odd numbers.
For 2 Odd numbers (Considering that the final answer is an integer)
(i) Odd + Odd = Even
(ii) (Odd - Odd) = Even
(iii) Odd / Odd = Odd
Therefore m - n will result in an odd number.