One way to reduce the effects of pollution is to prevent some of it from entering the environment in the first place. What is happening to this wastewater?

A. It is being used as fertilizer on a farmer's fields
B. It is being cleaned in a wastewater treatment plant.
C. It is being contaminated further from outside sources.
D. It is being held temporarily in a wastewater treatment plant until it is
released in its original condition back into the environment.