The OA is C, which I disagree with.
a^2 - b^2 = 16
While attempting the problem, I tried a few combinations of numbers and figured out that a=5 and b=3.
Possibilities are: 1 * 16, 2*8, 4*4. But only 2*8 would work here for the equation to make sense.
So for the answer, I put A.
What about a= -5 and b=-3? I think you need statement 2.