FastMart, a convenience store chain, is planning to add pancake syrup to the items it sells. FastMart stores do not have shelf space to stock more than one variety of syrup. Surveys of FastMart customers indicate that one-fourth of them prefer low-calorie syrup, while three-fourths prefer regular syrup. Since FastMart’s highest priority is to maximize sales, the obvious strategy for it is to stock regular syrup.
Which of the following, if true, most seriously weakens the argument?
A. People buying pancake syrup at convenience stores, unlike those buying it at supermarkets, generally buy it only a few times.
B. People who prefer low-calorie syrup generally use about the same amount of syrup on their pancakes as those who prefer regular syrup.
C. Regular syrup does not sell for a higher price per unit than low-calorie syrup.
D. In general, customers who prefer regular syrup will buy low-calorie syrup if regular is unavailable, but those who prefer low-calorie will not buy regular syrup.
E. Sales of syrup are not expected to account for a large proportion of total dollar sales at the average FastMart store.
FastMart, a convenience store chain, is planning to add pancake syrup to the items it sells. FastMart stores do not have shelf space to stock more than one variety of syrup. Surveys of FastMart customers indicate that one-fourth of them prefer low-calorie syrup, while three-fourths prefer regular syrup. Since FastMart’s highest priority is to maximize sales, the obvious strategy for it is to stock regular syrup.
Which of the following, if true, most seriously weakens the argument?
A. People buying pancake syrup at convenience stores, unlike those buying it at supermarkets, generally buy it only a few times. （根本没有在两种syrup比较，无关项）
B. People who prefer low-calorie syrup generally use about the same amount of syrup on their pancakes as those who prefer regular syrup.（买低热量版的人不会一次多买一点，那么根据“购买人数*单个消费者购买量”，当然是哪种买的人多就卖哪种，应该是常规班，支持项）
C. Regular syrup does not sell for a higher price per unit than low-calorie syrup.（常规版的价格<=低热量版的价格。其实，仅仅这一信息，既不支持，也不反对）
D. In general, customers who prefer regular syrup will buy low-calorie syrup if regular is unavailable, but those who prefer low-calorie will not buy regular syrup.（没有常规版，人们就会买低热量版，这样所有人都会买syrup，这比卖常规版时只有75%的人会买syrup人数更多，那么这就让我们更相信卖低热量版是个好选择，驳斥项）
E. Sales of syrup are not expected to account for a large proportion of total dollar sales at the average FastMart store.（根本没有在两种syrup比较，无关项）
所以D是正确的。其实驳斥项并不一定导致原结论的反面。比如这一题，在D成立的情况下，我们就一定能得出卖低热量版比卖常规版销售额更大么？不能。
因为，销售额=销量*单价，这里只说了销量会增加，单价呢？我们不知道。
但是，这是正确答案，因为驳斥项的只被要求让人们更相信原结论不太可能发生。
其实如果把D这样改写，就是一个支持项。
In general, customers who prefer regular syrup will buy low-calorie syrup if regular is unavailable, but those who prefer low-calorie will not buy regular syrup. However, the price for regular syrup is at least one-third more than that of low-calorie syrup.作者: chaomat1988 时间: 2012-12-19 19:43
