费费逻辑网络课堂里的一道题目

16. Twenty percent of all energy consumed in the United States is consumed by home appliances. If appliances that are twice as energy- efficient as those currently available are produced, this figure will eventually be reduced to about ten percent.

The argument above requires which of the following assumptions?
(A) Home-appliance usage would not increase along with the energy efficiency of the appliances.(B) It would not be expensive to produce home appliances that are energyefficient.
(C) Home-appliance manufacturers now have the technology to produce appliances that are twice as energy-efficient as those currently available.
(D) The cost of energy to the consumer world rise with increases in the energy efficiency of home appliances.
(E) The percentage of energy consumed by home appliances will increase if existing appliances are not replaced by more energy-efficient models.

我在听费费的逻辑网络课程的时候对这个题目仍然不太认同。费教我们用not +削弱的方法来判断五个assumptions中正确的那个。答案是a,可是e为什么不对呢？撇开not不读，剩下的肯定句明明是对题目中说法的削弱呀，与not再合用的话不就成了对题目所require的假设了吗？那位大侠能为我解释一下吗？谢谢大家了！