Which of the following is an integer?
I. 12! / 6!
II. 12! / 8!
III. 12! / 9!6!  Select:
A) I only
B) II only
C) III only
D) I and II only
E) I, II, and III
12!/6! = 12*11*10*9*8*7 which is an integer.   12!/8! = 12*11*10*9 which is an integer.   12!/9!6! = 12*11*10/ 6*5*4*3*2 = 11/6 which is not an integer.   The answer is I and II only.
<result>D</result>
Which of the following is an integer?
I. 12! / 6!
II. 12! / 8!
III. 12! / 9!6!