This is a boldface role question, so first find the argument's main conclusion, then name what each boldfaced portion does relative to it. The unbolded sentence "This concern is not well founded" is the author's main conclusion. The first boldface states the managers' prediction that sales will drop once shoppers in unfamiliar markets encounter the house brand. That prediction is precisely the concern the author calls unfounded, so the first portion is a prediction the argument seeks to discredit. The second boldface reports that in the three regions that already carry the house brand, its share of snack sales has climbed steadily over the past two years. The author uses this record to show the prediction is wrong, so the second portion is evidence presented to undermine that prediction. Choice A names both roles correctly.
Choice B treats the first portion as supporting evidence and the second as the conclusion, but it inverts both roles: the first is the rejected prediction and the second is the counter-evidence, not the conclusion.
Choice C calls the first portion the main conclusion, but the actual conclusion is the unbolded sentence declaring the concern unfounded; the first portion is the view the author opposes.
Choice D uses opposition-flavored language yet reverses the direction: the argument disputes the first prediction rather than endorsing it, and the second finding refutes the prediction rather than being a concession that weakens the author's case.
Choice E swaps the labels, calling the first portion evidence when it is the forecast itself, and saying the argument accepts that forecast as well founded when it in fact rejects it.