Concept:Soil erosion occurs when topsoil is removed by water or wind.
Protecting the soil surface is the best way to prevent it.
Explanation:Cover-cropping means planting crops such as grasses or legumes over the soil.
Plant roots bind the soil particles and make the soil firm.
Leaves and stems reduce the force of raindrops and wind on the ground.
This lowers surface runoff and keeps the fertile topsoil in place.
Flooding a farmland increases water flow and removes soil.
Deforestation removes the protective roots and canopy of trees.
Leaving the soil bare exposes it directly to wind and rain.
Therefore, cover-cropping is the most effective method among the options.
Answer:B. cover-cropping