单选题 If Blankenship Enterprises has to switch suppliers in the middle of a large production run, the company will not show a profit for the year. Therefore, if Blankenship Enterprises in fact turns out to show no profit for the year, it will also turn out to be true that the company had to switch suppliers during a large production run.
The reasoning in the argument is most vulnerable to criticism on which one of the following grounds?

A、 The argument is a circular argument made up of an opening claim followed by a conclusion that merely paraphrases that claim
B、 The argument fails to establish that a condition under which a phenomenon is said to occur is the only condition under which that phenomenon occurs
C、 The argument involves an equivocation, in that the word "profit" is allowed to shift its meaning during the course of the argument
D、 The argument erroneously uses an exceptional, isolated case to support a universal conclusion
E、 The argument explains one event as being caused by another event, even though both events must actually have been caused by some third, unidentified event

【正确答案】 B

【答案解析】[解析] 改变供货商，只是Blankenship企业这一年不会有利润的的一个条件，因此论述中把该条件当作不会有利润的惟一条件是不合适。要使它的结论成立，它就必须证明改变供货商是这一年不会有利润的充要条件。由此分析可知选项(B)是正确答案，其余四个选项都不合适。