The formation of black soil of the Deccan Plateau is linked with which original rock base?

Correct answer: Basaltic lava rocks

The governing concept is the relationship between parent rock and soil formation. Much of the Deccan Plateau is made of old basaltic lava flows known as the Deccan Traps. Long-term weathering and breakdown of these dark, iron- and magnesium-rich rocks produced the characteristic black or regur soil. Therefore option B is correct. Coral rocks do not form the broad interior soil cover of the Deccan, marine sand is associated with coastal environments, and glacial deposits are typical of areas affected by former ice movement. The answer follows the geology of the plateau rather than simply the colour of the soil.