求教：prep-ps

For every positive even integer n, the function h(n) is defined to be the product of all the even integers from 2 to n, inclusive.  If p is the smallest prime factor of h(100) + 1, then p is

(A) between 2 and 10

(B) between 10 and 20

(C) between 20 and 30

(D) between 30 and 40

(E) greater than 40

这类题有什么快捷的方法吗？

请各路大侠指教！！！谢谢！！！

h(100)应该是2的50次方*50！,再加1的话，就不可能是2-50之间任何数的倍数