What are the rock chambers in ancient india used for

The earliest rock-cut garbhagriha, similar to free-standing ones later, had an inner circular chamber with pillars to create a circumambulatory path (pradakshina) around the stupa and an outer rectangular hall for the congregation of the devotees

(b) britain had a much larger navy than the u.s.

(d) the u.s. had a small army compared to britain.