[求助]一道题逻辑题

8.(Z)Which of the following most logically completes the argument?

The irradiation of food kills bacteria and thus retards spoilage.  However, it also lowers the nutritional value of many foods.  For example, irradiation destroys a significant percentage of whatever vitamin B1 a food may contain.  Proponents of irradiation point out that irradiation is no worse in this respect than cooking.  However, this fact is either beside the point, since much irradiated food is eaten raw, or else misleading, since _______.

A.   many of the proponents of irradiation are food distributors who gain from food’s having a longer shelf life

B.   it is clear that killing bacteria that may be present on food is not the only effect that irradiation has

C.   cooking is usually the final step in preparing food for consumption, whereas irradiation serves to ensure a longer shelf life for perishable foods

D.  certain kinds of cooking are, in fact, even more destructive of vitamin B1 than carefully controlled irradiation is

E.   for food that is both irradiated and cooked, the reduction of vitamin B1 associated with either process individually is compounded

E是正确答案 请牛人解释一下为什么E对 （可以的话最好能简单翻译一下E ，我对剧中compounded的意思很不懂）

非常感谢

我的理解:

E 的翻译: 对于那些同时被辐射和烹调过的食物, 食物中维生素B的含量下降的效果是叠加的(COMPOUNDED).

E 的解释: 即辐射和烹调都对维生素B有摧毁作用, 例如: 食物在出厂前被辐射,维生素B含量从100降低到70, 在食用前被烹调,维生素含量从70降低到40.那么,辐射的效果是降低30,烹调的效果是降低30,那么我们是否能说,因为辐射的效果与烹调的效果差不多,那么辐射就是好的呢? 显然不能,因为如果不经过辐射,我们还可以吃到含有70含量维生素的食物,可是经过辐射,我们就只能吃到40的了.