题目选项分析

About 857 million silver-colored "Susan B . Anthony" dollars that the United States minted between 1979 and 1981 proved unpopular because it looked and felt too much like a quarter.

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.