The Correct Answer is : Volcanic origin Explanation & Key Takeaways: • Black soil, also known as Regur soil, is mainly found in the Deccan Plateau region of India. This region includes parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and Tamil Nadu. • The primary reason for the formation of black soil is the weathering, i.e., breaking down or disintegration, of volcanic rocks and lava. • This type of soil is rich in minerals such as calcium carbonate, magnesium, potash, and lime which are favorable for growing cotton. As a result, the black soil is also often referred to as "Black Cotton Soil". • Black soils are known for their high moisture retention capacity. Therefore, these soils are suitable for dry farming. • The soil is deep and fine-grained, with rich humus content. • Black soil swells and becomes sticky when wet and shrinks when dried. As a result, during the dry season, the soil often develops wide cracks. • India's black soils tend to be clayey, more in the nature of a heavy loam, and usually are quite rich in their phosphate content.