Answer: B. Running water cuts small channels into a slope.
In rill erosion, the soil is removed by the concentrated flow of water. In this form of erosion, water forms very small channels throughout the soil as it flows and is transported. In rill erosion, the soil is weathered, transported, and deposited as a result of the intensive action of running water through a series of tiny head cuts and streamlets. Rill erosion is triggered by poorly saturated soils, high rainfall intensity, steep slopes, and the nature of the soil itself.