Inorganic parent material transported by gravity is

Answer: Option D

Colluvial is an inorganic material transported by gravity.
It is a general name for loose, unconsolidated sediments that have been deposited at the base of hillslopes by either rainwash, sheet wash, slow continuous downslope creep by unconcentrated surface runoff or sheet erosion.
Thick accumulations of colluvium may preserve a rich record of long-term paleoclimatic change based on the paleosols and the remains of plants and animals.