It is clear from the passage that Chevies refer to ______.

D
本题为细节题。根据文章第1段最后一句He said it was a 1950 or 1951 Chevrolet．和第2段第1句中的Ordinarily，searching through the files for owners of elderly Chevies would have been an impossibly difficult task because there were two and a half million such cars．我们不难看出Chevrolets与Chevies所指的是同一个东西，故应选D。