Problem Solving

Hi guys,

Can someone explain how to solve this question:

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

Thanks!