Hint: Topsoil is the uppermost layer of the Earth's surface layers which is caused by the water and wind to be removed.
1) Soil tilling: Tilling is simply turning over and breaking up the soil. The soil depends on the reason for tilling exactly how deep you till and how fine you break up. You can purchase or rent an engine-powered tiller from a garden supply center to make the task of tilling easier.
2) Soil erosion: Soil erosion is a naturally occurring process that affects all landforms. By the natural physical forces of water and wind or through forces associated with farming activities such as tillage, soil erosion refers to the wearing away of a field's topsoil in agriculture.
3) Soil mulching: Mulching is the placement of any organic or inorganic material over the top of a soil surface to protect it. Some of the benefits include: reduced soil erosion, less compaction, moisture conservation, increased control of soil temperature, and a reduction in weed growth.
4) Weathering: Biological weathering is weathering caused by plants and animals. Plants and animals cause weathering with releasing acid forming chemicals and also contribute to the breaking down of rocks and landforms. By breaking down of rocks and landforms the chemical weathering has been caused.
The option B: Soil erosion is the correct answer.
Note: Topsoil is the uppermost layer of the Earth's surface layers which is caused by the water and wind to be removed. This process of carrying off top soil by wind and water is called soil erosion.