问兄弟姐妹一个数学题目,实在不会做啊.............................

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

不知道答案是什么,望高人指教!万分感谢!!!

h(100)= 2*4*6............100
h(100)+1=2*4*6............100 +1
2(1*2*3.......50)+1

so when h(100)+1 is divided by any of the nos between 2 and 50 will leave a remainder 1.

2*50!+1 will not be divisible by any no <50

ANS E

这是我在GOOGLE上搜索的一个美国人GMAT复习网站上人家的讨论，觉得蛮有道理的。你看看吧