What Is the Geologic Norm with Reference to Erosion

What is the geologic norm with reference to erosion?

A) The average amount of sediment eroded from an unvegetated surface
B) The natural rate of erosion on a vegetated surface that still allows soils to be maintained
C) The rate of erosion normally found where vegetation is removed and overland flow is allowed to progress naturally
D) The probability of severe erosion should all natural vegetation be removed
E) The rate of erosion in humid regions where rainfall is consistent and vegetation is regularly removed.