还是一道GWD

xingxc11

33: GWD-29-Q38
In the past, every ten-percentage-point increase in cigarette prices in the country of Coponia has decreased per capita sales of cigarettes by four percent.  Coponia is about to raise taxes on cigarettes by 9 cents per pack.  The average price of cigarettes in Coponia is and has been for more than a year 90 cents per pack.  So the tax hike stands an excellent chance of reducing per capita sales of cigarettes by four percent.
Which of the following is an assumption on which the argument depends?

A.    Tobacco companies are unlikely to reduce their profit per pack of cigarettes to avoid an increase in the cost per pack to consumers in Coponia.
B.    revious increases in cigarette prices in Coponia have generally been due to increases in taxes on cigarettes.
C.    Any decrease in per capita sales of cigarettes in Coponia will result mainly from an increase in the number of people who quit smoking entirely.
D.    At present, the price of a pack of cigarettes in Coponia includes taxes that amount to less than ten percent of the total selling price.
E.    The number of people in Coponia who smoke cigarettes has remained relatively constant for the past several years
这道题选A 我是这样理解题目的：香烟价格提升10个百分点，销量就下降4个百分点，C给每包香烟提升9%的税，于是香烟的价格每包比过去多了90cents.所以加税是使得香烟销量下降的好方法。
问假设。
我的思路是：eliminate alternate paths to reach a given conclusion.
A 说：他们不会冒着降低利润的风险来增加成本。所以只能通税来降低成本。脑子很混乱，不知道正确的思路是什么？欢迎拍砖！！！！

ashcroft

the given causal link： rise price-----decrease per capita sales of cigars.
situation: C is about to raise taxes in order to raise the price, so that decrease cigar sale.
这里我们显然可以看出，raise tax和raise price之间是存在一个flaw的，提高税率就一定能提高价格，这是题目的assumption所在，所以只要确保提高税率就能提高香烟价格的选项就是答案。A显然就是确保了提税就能提价，正确。