In the past, American cities emptied their sewage into rivers and other bodies of water. This caused the bodies of water to be polluted and filled with microorganisms that could cause human diseases.

Today, people understand how bad it is for the environment to dispose of raw sewage in rivers, lakes, and bays.

How do most American cities now protect their water resources?
A.
They only use groundwater, instead of surface water, for their drinking water supply.
B.
They send sewage to a water treatment plant.
C.
They flush local bodies of water every 10 years.
D.
They dispose of raw sewage in rural locations.