Why Would Soil and Water Be Added to a Compost

Why would soil and water be added to a compost pile?

A) The organisms in the soil, along with the moisture from the water, would facilitate the natural decomposition of the material in the compost pile.
B) Without adding soil and water, no decomposition of the material can take place. The material would simply sit there.
C) Water is the medium that photosynthetic organisms use to break down the organic materials in the compost pile.
D) Soil spreads out the material in the pile. If the material is too close together, natural aeration cannot occur and decomposition stops.