which outlines the effect of root wedging?

a as water in cracks of rocks turns to ice, the crack becomes larger
b as rocks begin moved by wind hit other rocks, the rocks being hit are broken down
c as plant roots in cracks of rocks grow, the crack grows as well
d as pressure from the earth's crust increases, the top layer of the rock cracks

c as plant roots in cracks of rocks grow, the crack grows as well