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