If a is an integer greater than 6, which of the following must be divisible by 3?  Choose the correct choice from the following choices.
A) a (a+5) (a-6)	B) a (a+2) (a-1)	C) a (a+3) (a-5)	D) a (a+4) (a-2)	E) a (a+1) (a-4)
anything in the form of (a-1) (a) (a+1) is divisible by 3. in other word, a product of any 3 consecutive intevers is divisible by 3.   a (a+1) (a-4) = a (a+1) ((a-1)-3) is equivalant to (a-1) (a) (a+1)   a (a+2) (a-1) is equivalant to (a+1) missing.   a (a+3) (a-5) is equivalant to (a-1) missing and a repeating.   a (a+4) (a-2) is equivalant to odd/even consqcutive integers   a (a+5) (a-6) is equivalant to (a+1) missing and a repeating.   Answer : a (a+1) (a-4)
<result>E</result>
If a is an integer greater than 6, which of the following must be divisible by 3?