n is a positive integer and k is the product of all integers from 1 to n inclusive. If k is a multiple of 1680, then what is the smallest possible value of n? Choose the correct choice from the following options.
A) 4  B) 6  C) 7  D) 10  E) 12
3360=2^4*3*5*7   2^4 means that n must be at least 6. That is, We need 2, 4, and 6.   However, we also need 7, so n must be at least 7.   The answer is 7.
<result>C</result>
n is a positive integer and k is the product of all integers from 1 to n inclusive. If k is a multiple of 1680, then what is the smallest possible value of n?