If n is the greatest positive integer for which 4^n is a factor of 10!, then n =? Choose the correct choice from the following answers.
A) 2
B) 4
C) 6
D) 8
E) 10

Rationale: 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 ! b is answer
Answer: B