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. Ttherefore, 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? ['The argument is a circular argument made up of an opening claim followed by a conclusion that merely paraphrases that claim.', '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.', '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.', 'The argument involves an equivocation, in that the word "profit" is allowed to shift its meaning during the course of the argument.']