The Farmer's Almanac is predicting that the next two years will yield

Choice E is good because if the main reason for buying is not connected to the rain then we can safely infer that option

The Farmer's Almanac is predicting that the next two years will yield 20 percent less rain in the Pacific Northwest. As a result, local merchants are lowering their sales expectations for rain suits by the same percentage.

Conclusion- local merchants are lowering their sales expectations for rain suits by 20%
Type-weaken
The argument establishes causality between the amount of rain and the sale of rain suits

A) Sales of all rainwear have been steadily increasing for the last decade.- irrelevant, we don't know the trend of rainfall in the last decade

B) The forecast for lower rainfall is not limited to the Pacific Northwest but is consistent with predictions nationwide.- irrelevant

C) On average, consumers who purchase rain suits keep them for three years.- incorrect; we don't know when customers in the Pacific Northwest last bought the rain suits

D) The Farmer's Almanac has correctly predicted the climate in the Pacific Northwest for the past fifteen years.- irrelevant

E) Research has demonstrated that most consumers purchase rain suits for their comfort and not because of the rain.- Correct, there is no causal relationship and thus our argument falls apart

Answer E

KAPLAN OFFICIAL EXPLANATION

The phrase "casts the greatest doubt" identifies this as a Weaken question. The correct answer will make the conclusion less likely. The author argues that merchants are lowering their sales forecasts for rain suits based on the Almanac's prediction of less rain.

The author assumes that a prediction of less rain will reduce the number of people buying rain suits. The correct answer will be anything that weakens this assumption. Perhaps the Farmer's Almanac is known to be unreliable. Or perhaps people will still buy rain suits despite the prediction. Keep the general prediction firmly in mind, but be flexible in applying it to the specific situations in the choice.

(E) is correct. If consumers purchase rain suits for reasons other than rainfall, then this weakens the link between the rain forecast and consumers' purchasing decisions.

(A) discusses the past and not the future and is therefore irrelevant.

(B) is irrelevant since the forecast for other regions has no bearing on the wisdom of the merchants' logic.

(C) is irrelevant. The argument hinges on the demand for rain suits in the coming year when presumably the people with three-year-old suits will consider replacing them based on the weather.

(D) is a strengthener, since the prediction of the Farmer's Almanac gains credibility.

TAKEAWAY: Weaken an argument with any conditions that may make the connection between the evidence and conclusion less likely.