GMAT Critical Reasoning (CR) | Re: Because of steep increases in the average price per box of

Answer choice A gives a probable reason why the prices have increased over a period of 10 years. Nothing about how likely is the plan of the manufacturers to improve sales works out.
The answer choice (question to ask to evaluate) should be something that should question the validity of the conclusion which the manufacturers made i.e., "likely that the level of overall sales of cereal will rise significantly, because of a wholesale price cut of 20%"
Answer choice D is the only one that
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