Which plain is important for delta formation on India’s eastern coast?

Correct answer: Eastern Coastal Plain

The direct answer is B, the Eastern Coastal Plain. A delta forms where a river slows down near its mouth and deposits silt, sand, and clay. India’s eastern coast is broad and comparatively gentle, so large rivers such as the Mahanadi, Godavari, Krishna, and Kaveri can build large deltas there. Reasoning step by step: rivers carry sediment; their speed decreases near the sea; sediment is deposited; a triangular or fan-shaped delta develops; the eastern coastal plain provides the important setting for these deltas. Option A, the Western Coastal Plain, is narrow and has many estuaries because rivers descend quickly to the Arabian Sea, so it is less associated with large deltas. Option B is correct because the eastern coast contains major deltaic plains. Option C, the Northern Mountains, are the source region of many rivers, but they are not the coastal depositional plain where these deltas form. Option D, the Indian Desert, is dry and inland, so it cannot be the main eastern coastal delta region. Remember: east coast is broad, rivers deposit, and deltas grow.