If n is the greatest positive integer for which 4^n is a factor of 10!, then n =?  Select the correct option
A) 2	B) 4	C) 6	D) 8	E) 10
10! = 3628800   E. 4^10 = 1048576 (3628800/1048576) - this is not a factor of 10!   D. 4^8 = 65536 (3628800/65536) - this is not a factor of 10!   C. 4^6 = 4096 (3628800/4096) - this is not a factor of 10!   B. 4^4 = 256 (3628800/256) - this is a factor of 10!   4 is answer
<result>B</result>
If n is the greatest positive integer for which 4^n is a factor of 10!, then n =?