The burning of fossil fuels provides energy for humans to use, but it also can have negative effects. For example, when large power plants burn fossil fuels, certain chemicals are released in the atmosphere that react with water vapor, resulting in acidic precipitation. This phenomenon is known as acid rain. Acid rain has had an adverse effect on ecosystem diversity throughout the world.

Which of the following would best decrease acid rain levels and reduce the human pollution impact on the environment?
A.
regulation of human outdoor activity
B.
chemical treatment of the soil that has been affected by acid rain
C.
chemical treatment of the water that has been affected by acid rain
D.
regulation of factory emissions