Corporate Officer: Last year was an unusually poor one for our chemical division, which has traditionally contributed about 60 percent of the corporationâ€™s profits. It is therefore encouraging that there is the following evidence that the pharmaceutical division is growing stronger: it contributed 45 percent of the corporationâ€™s profits, up from 20 percent the previous year.
On the basis of the facts stated, which of the following is the best critique of the evidence presented above?
(C) The percentage of the corporationâ€™s profits attributable to the pharmaceutical division could have increased even if that divisionâ€™s performance had not improved.
IMO, this CR asks about the assumption which weakens the conclusion, and the type of this assumption question is cause-and-effect.
To find the correct answer choice, it's best to ask whether there're alternative causes. Here, the increase in contribution of pharmaceutical division to the company's profit may not be due to the improvement in performance but due to the decreased contribution level of chemical division ( that's why this CR mentions about "chemical division" )
C provides us an open to alternative causes.
Go for C.