The correct answer is D. All of these.
Khadar, Bangar, and Doab are all areas of Haryana that are characterized by different types of soil. Khadar soils are found in the floodplains of rivers and are relatively fertile. Bangar soils are found on higher ground and are less fertile. Doab soils are found between two rivers and are a mixture of Khadar and Bangar soils.
Khadar soils are formed by the deposition of silt and clay from rivers. They are typically dark in color and have a high water content. Khadar soils are well-suited for growing rice, wheat, and other crops.
Bangar soils are formed by the weathering of rocks. They are typically light in color and have a low water content. Bangar soils are not as well-suited for growing crops as Khadar soils, but they can be used for grazing livestock.
Doab soils are a mixture of Khadar and Bangar soils. They are typically brown in color and have a moderate water content. Doab soils are well-suited for growing a variety of crops, including rice, wheat, sugarcane, and cotton.