What Are Exotic Rivers

What are exotic rivers?

A) Rivers that contain such a broad array of pollutants that they no longer function in the way they would under natural conditions.
B) Rivers that cross urbanized areas and so are considerably changed from their natural state.
C) Rivers that cross a variety of terrains including changes in vegetation and elevation
D) Rivers that do not flow all year round and that may remain dry for possibly many years
E) Rivers that flow through arid regions although the source of their water derives from regions with a water surplus