Question

What is the best interpretation of the equation below if a and b are integers, and a b.

(2a + 1)(2b + 1) = 2(2ab + a + b) + 1
The product of an odd integer and an even integer is an odd integer.

The sum of two even integers is an odd integer.

The product of two odd integers is an odd integer.

The product of two even integers is an odd integer.