Which type of rocks is considered important in the formation of the Deccan Plateau?

Correct answer: Basaltic volcanic rocks

Option B is correct because large parts of the Deccan Plateau, especially the Deccan Trap region, are formed from layers of basalt produced by extensive ancient volcanic lava flows. Basalt is a dark, fine-grained volcanic rock rich in iron and magnesium. Over long periods, weathering of these basaltic rocks contributed to the development of black cotton soil, which is important for agriculture in parts of the plateau. Glacial rocks are not the defining material of the Deccan, coral rocks belong to marine environments, and marine sandstone does not explain the characteristic lava-sheet structure of the Deccan Trap. Thus the geological clue points to B.