Rocky material from the Earth's interior can reach the surface, and be pushed and folded upward during the process of . One of the processes that works to return this material back to the Earth's interior is .
A.
erosion; mountain building
B.
weathering; mountain building
C.
weathering; erosion
D.
mountain building; erosion

Rocky material from the Earth's interior can reach the surface, and be pushed and folded upward during the process of mountain building. One of the processes that works to return this material back to the Earth's interior is erosion.

Explanation:

The process of mountain building is known as Orogenesis. The Greek word Orogenesis derived from Oros means mountain and Genesis means formation. Due to the tectonic movements sometimes earth's interior's materials pushed to the earth's surface and get folded and rise upward this is known as mountain building. In this way fold mountains are formed.

When the newly formed folded structure undergo some sorts of changes due to the erosional activities by the agents of nature like air, water, glacier etc. known as erosion.  

the answer is b i think