[求助]新PrepI-248

248. The United States minted about 857 million silver-colored “Susan B. Anthony” dollars between 1979 and 1981, but the coin proved unpopular because it looked and felt too much like a quarter.

A. The United States minted about 857 million silver-colored “Susan B. Anthony” dollars between 1979 and 1981, but the coin

B. About 857 million silver-colored “Susan B. Anthony” dollars were minted as coins in the United States between 1979 and 1981 but

C. About 857 million silver-colored “Susan B. Anthony” dollars that were minted between 1979 and 1981 in the United States

D. About 857 million silver-colored “Susan B. Anthony” dollars that the United States minted between 1979 and 1981

E. Between 1979 and 1981 the United States minted about 857 million silver-colored “Susan B. Anthony” dollars, which

Given answer is A.

我选B的原因是我认为A的"the coin"前文中并没有提及，我怎么知道"Susan B. Anthony" dollars是coin呢；此外让我一直想不通的是此处prove的用法，难道不应该是the coins were proved to be unpopular简化为the coin proved unpopular吗，为何除了B以外的答案都是主动语态？

新版讨论并没有收录此题，望NN解惑