If n is the greatest positive integer for which 2^n is a factor of 6!, then n =? Choose the correct option:
A) 2 B) 4 C) 6 D) 8 E) 10
6! = 720   E. 2^10 = 512 (720/512) - this is not a factor of 6!   D. 2^8 = 256 (720/256) - this is not a factor of 6!   C. 2^6 = 64 (720/64) - this is not a factor of 6!   B. 2^4 = 16 (720/16) - this is a factor of 6!   4 is answer
<result>B</result>
If n is the greatest positive integer for which 2^n is a factor of 6!, then n =?