If 200!/10^n is an integer, what is the largest possible value of n?  Select.
A) 40 B) 42 C) 44 D) 48 E) 49

Rationale: "we have to basically count the number of 5 s withing 200 200 / 5 = 40 200 / 5 ^ 2 = 8 200 / 5 ^ 3 = 1 we know for sure that there will be at least 49 even numbers ( multiples of 2 ) within 200 so there are 49 10 s in 200 ! answer : e"
Answer: E