Answer the following question given this paragraph: 

Water treatment is a series of processes that remove unwanted substances from water. The goal of water treatment is to make the water safe to return to the natural environment or to the human water supply. Treating water for other purposes may not include all the same steps. That’s because water used in agriculture or industry may not have to be as clean as drinking water.


Q: What is a series of processes that remove unwanted substances from water called?

 Choices:

- water filtration

- water dilution

- water cleaning

- water treatment

A:
water treatment
