A subsoil includes

Answer: Option B

The subsoil is the layer of soil under the topsoil on the surface of the ground. It is composed of a variable mixture of small particles such as sand, silt and clay, but with a much lower percentage of organic matter and humus, and it has a small number of rocks that are smaller in size mixed with it.
The subsoil is also called a B horizon found just beneath A horizon or topsoil.