Option A — Alluvial Soil is correctly matched with the Gangetic Plain (northern plains). Black soil is found in the Deccan plateau region, not the Himalayan region.
The textbook clearly states that the entire northern plains, including the Gangetic Plain, are made of alluvial soil deposited by Himalayan river systems. Black soil is typical of the Deccan trap (Maharashtra, Malwa, etc.), laterite soil is found in Western Ghats and southern states, and arid soils are found in Rajasthan — not the Western Ghats. Always remember the soil–region mapping for MCQs.