Why Was the Clean Air Act Amended in 1990

Multiple Choice

Why was the Clean Air Act amended in 1990?

A) to reduce sulfur dioxide emissions from electric power plants to half of 1980 levels
B) so flat fees for excessive pollution could be determined by the federal government
C) to reduce sulfur dioxide emission through command-and-control regulations
D) to reduce sulfur dioxide emissions from electric power plants to half of 1970 levels