Concept:River erosion involves different processes that describe how a river scours and transports material.Explanation:The wearing away of the sides and bottom of a river channel is caused by the scraping action of rock particles carried by the river.This mechanical grinding of the river bed and banks is called corrasion.Corrosion is the chemical erosion of rocks by acidic water.Suspension is the process where fine particles are carried within the water.Solution is the process where minerals dissolve directly into the water.Answer:C. corrasion