OG12-99 求请教

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 proponets of irradiation are food distributors who gain from foods'having a longer shelf life
(B)it is clear that killing bacteria that may be present on food is not the only effect that irradition has
(C)cooking is usually the final step in preparing food for consumption, whereas irradiation serves to ensure a irradiation is
(D) certain kinds of cooking are,in fact, even more destructive of vitamin B1 than the 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
我不明白E选项是怎weaken结论辐射支持者的观点的，OG解释里说if the effects of radiation and cooking combine to destory more B1 than cooking or irradion alone would,then the
proponents'claim suggests something that is false.这个说法好像和答案E的削弱不一样，OG的这句解释感觉并没有削弱，两者之和本来就比单一的一种cooking 或irradiaton毁坏的B1来的多。请教！！！！