What is the most suitable reason for marshy conditions in the Terai region?

Correct answer: Re-emergence of underground water

The direct answer is A: underground water re-emerges at the surface. The Terai lies south of the Bhabar belt. In the porous Bhabar, streams and underground water often disappear into coarse pebbles. Farther south, the finer and less permeable Terai material prevents easy downward movement, so the water comes back to the surface. This creates wet, marshy, and sometimes waterlogged conditions. Option A is correct because it describes this underground-to-surface water movement. Option B is wrong because desert-wind deposition is associated with arid regions, not the main explanation for Terai marshes. Option C is wrong because broken lava rocks do not explain the Terai’s characteristic wetness. Option D is wrong because direct glacier melting is not the defining process there. Memory cue: Bhabar absorbs water; Terai brings it back.