GMAT Critical Reasoning (CR) | Re: The Maxilux car company's design for its new luxury model,

(D). Profit = Revenue - Cost. The premises show that revenue from Maxilux will equal cost. So to strengthen the argument, we need additional revenue from elsewhere. (B) is close because it generates additional revenue, but that revenue is also from Maxilux so the revenue will most likely not exceed the cost here either. (D) is the only answer choice that adds the kind of outside revenue stream we want.