This is a strengthen question. The proposal involves releasing a new line of small, high-mileage, and hybrid vehicles, which don't appear to have previously been the company's strong suit. The argument assumes that releasing the new line will have the effect of increasing revenue without losing its current customer base. Consider each choice in turn:

(A) This choice suggests that the company has a lot of improvements to make, but it doesn't tell us whether those improvements, as suggested by the consultants, would have the desired impact.
(B) This is correct. The survey (a "reliable" one, so we don't have to worry about sampling issues) addresses the potential concern that the company would lose its previous customers, who were not customers of smaller or hybrid vehicles.
(C) This weakens the argument somewhat, suggesting that perhaps this car company's sales lagged only because of industry-wide declines.
(D) This is irrelevant. The argument is concerned with revenue, not with costs.
(E) As with (D), this choice is not relevant to expanding "revenue" base. Profit margins consider both revenue and cost. In order for this choice to be correct, we would need to know that developing this type of vehicle would cause revenues to shrink, not just profits.