Concept:Soil erosion is promoted by farming practices that remove or destroy the protective vegetation cover on the land.Explanation:Alley cropping involves growing crops between rows of trees or shrubs.This practice helps control erosion, so it does not promote soil erosion.Bush burning removes the natural vegetation cover by fire, exposing the soil to wind and water erosion.Overgrazing depletes the grass cover, leaving the soil bare and vulnerable to erosion.Therefore, only II and III promote soil erosion.Answer:C. II and III only