How Do Freezing, Thawing, Wetting, and Drying Contribute to Soil

How do freezing, thawing, wetting, and drying contribute to soil creep?

A) Gravity exerts a much stronger force when the soil is wet and thawed.
B) The soil becomes much weaker when dry and frozen.
C) The soil expands and contracts, lifting particles then lowering them a slight distance downslope.
D) Eventually these cause the soil and regolith to suddenly slide down the slope.