An artificial Levee is a human-made slope or wall placed alongside a body of water. Cities often Build artificial Levees along the banks of rivers to protect them from flooding. If One city builds a levee on a river, how will this most likely affect other cities down stream?

A. It will decrease their risk of flooding.

B. It will increase the number of fish in their part of river.

C. It will decrease the number of fish in their part of the river.

D. It will increase their risk of flooding.