Answer: B. allow water to soak in easily, preventing runoff.
Step-by-step explanation:
Soil Permeability is the ease at which water and air go into soil. A moderately permeable soil will therefore allow water and air to go to it easier and this prevents soil erosion.
Soil erosion from water happens when there is runoff but this will be less with moderately permeable soils because the water will sink into the ground faster and so will not runoff and carry the topsoil with it thereby preventing erosion.