The difference between the squares of two consecutive odd integers is always divisible by:

A.3
B.6
C.7
D.8
Ans: D

Explanation:

Let the two consecutive odd integers be (2x + 1) and  (2x + 3)
Then, (2x + 3)2 - (2x + 1)2 = (2x + 3 + 2x + 1) (2x + 3 - 2x - 1) = (4 x + 4) x 2
                                          = 8 (x + 1), which is always divisible by 8