Which of the following is an example of the U.S. government's use of a "command-and-control" approach to reducing pollution?

A) In 1990 Congress approved measures designed to reduce sulfur dioxide emissions to 8.5 million tons annually by 2010.
B) The government issued electric utilities tradable emission allowances in order to reduce emissions of nitrogen oxide.
C) In the 1980s the U.S. government required the installation of catalytic converters to reduce emissions from all new automobiles.
D) The U.S. government imposed a tax on electric utilities to reduce damages from acid rain.

C