Why D and not A?

Hi @Kahanding, thanks for your post. This is a Main Point question. Let's evaluate the stimulus carefully. P: Some people claim that the battery powered electric car represents a potential solution to the problem of air pollution. [Implied: But these people are wrong, because:] P: They forget that it takes electricity to recharge batteries, and P: That most of our electricity is generated by burning polluting fossil fuels P: Increasing the number of electric cars would require building more generating facilities, since current facilities are at max capacity SC: So even if all of the gasoline powered cars on the roads today were replaced by electric cars, it would at best be an exchange of one source of fossil fuel pollution for another. [Which is why C: the people who think that battery powered electric cars are the solution are wrong] Answer choice (D) is a correct statement of the main point of the stimulus. Answer choice (A) is not the overarching point of the stimulus. Rather, the statement regarding generating facilities is part of one of the premises supporting the overall conclusion. Hope this helps! Please let us know if you have any additional questions.