A classic example of a difference of squares equation:
x^2 - y^2
This equation consists of two perfect squares, x^2 and y^2. It also has 2 terms. We can factor this equation like this: (x-y)(x+y). If there were more than two terms, it would look different.
Also, the equation x^2+ y^2 is unfactorable. "Difference" means something minus another thing. Therefore, one term has to have a plus sign and one term has to have a minus sign.
In your question, we have determined that A, B, and C are all true, so the letter answer is B.
