What Is "Cohesion" as Applied to Slope Failure

Multiple Choice

What is "cohesion" as applied to slope failure?

A) the condition of a slope that has not yet begun to slide
B) loose grains in a slope that are angular rather than rounded so they don't slip past one another easily
C) the holding together of otherwise loose grains on a slope, often by a little moisture
D) grains in a rock that have interlocked as a result of metamorphism
E) grains in a granite or similar rock that don't separate easily