The correct answer to this question is D.  The two senators who sponsored this bill were John McCain, Republican from Arizona, and Russell Feingold, Democrat from Wisconsin.  This is why the bill was known as the McCain-Feingold law.

The major point of this bill was to reduce the amount of influence that could be wielded by “soft money” donors.  Soft money was money that was given to the political parties rather than to individual candidates.  There were no limits on such money and many people felt that it was a source of corruption in the political system.

The McCain-Feingold law was very unpopular among conservatives.  They feel that people should be allowed to spend as much money as they want putting out political messages.  Because of the power of the conservative bloc on the Supreme Court, much of the law was ruled unconstitutional in the Citizens United decision in 2010.