If n is a natural number, then 6n^ 2 + 6n is always divisible by?	Choose the correct option:	A) 6 only	B) 6 and 12	C) 12 only	D) 18 only	E) 20 only
6n^2 + 6n = 6n(n+1), which is always divisible by 6 and 12 both, since n(n+1) is always even.   Answer is 6 and 12
<result>B</result>
If n is a natural number, then 6n^ 2 + 6n is always divisible by?