to prevent wind from weathering and eroding surface coal. to prevent radioactive elements from polluting water sources. to provide an environment for new coal formation. to restore the area to a natural condition.
I gave my students this multiple choice question: Before strip mining for coal, the topsoil in the area is removed and stored. After mining operations are completed, the land is leveled and topsoil is replaced. The purpose of replacing topsoil is

Only one answer is correct among these 4 choices:
- to prevent wind from weathering and eroding surface coal.
- to prevent radioactive elements from polluting water sources.
- to provide an environment for new coal formation.
- to restore the area to a natural condition.

Could you tell me which one is correct?

to restore the area to a natural condition.