[求助]一道新东方的解释题！

zanyingsan

Surveys show that every year only 10percent of cigarette smokes switch brands.Yet the manufacturers have been spending an amount of equal to 10 percent of their gross receipts on cigarette promotion in magazines.It follows from these figures that inducing cigarette smokes to switch brands did not pay，and that cigarette companies would have been no worse off economically if they had dropped their advertising.

Of the following，the best criticism of the condition that inducing cigarette smokes to switch brands did not pay is that the conclusion is based on 

（A）computing advertising costs as a percentage of gross receipts，not of overall costs.

（B）past patterns of smoking and may not carry over to the future

（C）the assumption that each smokers is loyal to a single brand of cigarette at any one time

（D）the assumption that manufacturer products only one brand of cigarette

（E）figures for the cigarette industry as a whole and may not hold for a particular company

答案是E。我的问题是，如果放到反对的题目里出，我一定会选E，但是这道题放到解释里出，我觉得C这个选项也是可以的，请NN指点我的错误！谢谢！！！【全打出来不容易，拜托了！】

[此贴子已经被作者于2009/9/9 0:53:48编辑过]