Which is the greatest agent of erosion?

The answer should be option A "running water." Running water is the same as moving water which is the largest contributor to erosion. Moving water is compaction on the rock. Example of moving water is like waves slamming on rocks near shore which breaks away the rock which is erosion.

Hope this helps! 

The zhou dynasty (1046-256 bce) was the longest-lasting of china's dynasties. it followed the shang dynasty (c. 1600-1046 bce) and it finished when the army of the state of qin captured the city of chengzhou in 256 bce.

Don't depend on this but logically i think c