By which feature are Coastal Plains identified?

Correct answer: Level land along the sea

The direct answer is option A: Coastal Plains are level or gently sloping land beside the sea. The word coastal means related to a coast, and a coast is the land next to the sea. In India, coastal plains occur along the eastern and western seaboards; they are generally low-lying compared with nearby mountains and plateaus. Option A is correct because it combines the two identifying ideas: sea-side location and relatively level land. Option B is wrong because high Himalayan peaks belong to the Himalayan Mountains, far from the ordinary meaning of a coastal plain. Option C is wrong because the sandy land of the Thar belongs to the Indian Desert, not to coastal plains. Option D is less correct and refers to a rock characteristic, not the defining location and form of a coastal plain; old hard rocks are more associated with stable upland regions. Therefore A is the best answer. Memory cue: coast plus low, fairly flat land equals Coastal Plains.