The difference of the squares of two consecutive even integers is divisible by which of the following integers ?

Let the two consecutive even integers be 2n and (2n + 2). Then,

(2n + 2)² = (2n + 2 + 2n)(2n + 2 - 2n)

     = 2(4n + 2)

     = 4(2n + 1), which is divisible by 4.