Correct answer: A. Structure carved from a single rock
Explanation: Direct answer: Option A, a structure carved from a single rock. “Monolithic” means made from one large, solid stone or rock mass. In the Pancha Rathas, the craftspeople did not assemble separate bricks, wooden pieces or iron plates. They shaped the existing rock by cutting, removing and finishing parts of it until a temple-like form appeared. Therefore the exact meaning is a structure carved from a single rock. Option A is correct. Option B is wrong because wood is a separate material and is not the meaning of monolithic stone carving. Option C is wrong because a brick-built tower is assembled from many units, not cut from one rock. Option D is wrong because iron is not the material described here. The Pancha Rathas are associated with Pallava-period rock-cut architecture at Mahabalipuram. “Ratha” here refers to an architectural form, not proof that the buildings were ordinary movable chariots. Memory cue: mono means one; lith means stone—one stone, one carved structure.