What is the main feature of the Terai region?

Correct answer: Wet and marshy region

The Terai is a narrow, wet belt along the southern side of the Bhabar region, near the foothills of the Himalayas. In the porous Bhabar belt, streams often disappear into the coarse sediments. Farther south, these streams re-emerge and the ground becomes waterlogged, producing the marshy and humid Terai. Its wet conditions distinguish it from dry deserts, sandy areas, coral islands, and volcanic mountains.

Option A is correct because a wet and marshy region is the main geographical feature of the Terai. Option C describes a dry environment, which is the opposite of the Terai. Options B and D name unrelated landforms: coral islands are coastal or marine features, while volcanic mountains are formed by volcanic activity. The useful location clue is that Terai lies south of Bhabar in the Himalayan foothill zone.