Correct option is B
The correct answer is
(b) Densely populated due to fertile soil
Explanation: • Northern Plains are formed by alluvial deposits of rivers. • Extremely fertile soils (Bhabar, Terai, Khadar, Bhangar). • Support intensive agriculture → high population density. • Flat terrain promotes transport & settlement. • Known as the “food bowl of India.”
Information Booster: • Rivers shaping plains: Indus, Ganga, Brahmaputra.
Additional Knowledge: (a) Volcanic plateaus are in Deccan Plateau. (c) Northern Plains have low elevation. (d) Soil is fertile, not rocky.