Let the two consecutive even integers be n and n+2, where n is even.
The difference between their squares is:
(n+2)2−n2
Using the difference of squares formula a2−b2=(a+b)(a−b):
(n+2)2−n2=(n+2+n)(n+2−n)
=(2n+2)(2)
=4(n+1)
Testing divisibility by 2:
4(n+1)=2×2(n+1)
Always divisible by 2.
Testing divisibility by 3:
4(n+1) is divisible by 3 only when (n+1) is divisible by 3.
For n=2: 4(3)=12 is divisible by 3.
For n=4: 4(5)=20 is not divisible by 3.
Not always divisible by 3.
Testing divisibility by 4:
4(n+1) has 4 as a factor.
Always divisible by 4.
Testing divisibility by 5:
4(n+1) is divisible by 5 only when (n+1) is divisible by 5.
For n=2: 4(3)=12 is not divisible by 5.
Not always divisible by 5.
The difference is always divisible by 2 and 4, but not always by 3 or 5.
The answer is (A) and (C) only.