One thing people in the United States could do to reduce air pollution is

a. drive their cars more.

b. burn more fossil fuels.

c. use more public transportation.

d. build more factories.

Driving more cars would lead to more pollution: cars release gases that are also pollutants.

Also burning fossil fuels would lead more to pollution.

The correct answer is: c. use more public transportation. This would decrease the usage of private cars and decrease the pollution.