n is a positive even integer. H refers to a function where H(n) equals to the product of all the positive even integers from 2 to n, i.e., H(n) = 2 x 4.....(n-2) x n. p is the smallest prime factor of H(100)+1. what is p?
a) between 2~10; b) between 10~20; c) between 20~30; d) between 30~40; e) greater than 40.