Read the statements on rock-cut architecture and identify which one is true.

Given below are some statements about rock-cut architecture. Which of these is TRUE?

i. A lot of religious architecture was built or cut out of rock during the Vedic age; the remains of rudimentary sacrificial altars are evidence of the same.

ii. Rock-cut temples were hollowed out of mountains or seams carved out of hard stone, but have more in common with conventional buildings constructed with blocks of dressed stone than with sculpture.

iii. The transition from the earlier wooden to stone buildings resulted in 'petrification' of forms; the heritage of the earlier periods was carefully transcribed into new materials.

iv. The gigantic Kailasa temple at Ellora is the kind of rock-cut architecture exactly as the rathas at Mamallapuram where the monolithic building was carved straight out of living rock to create an occupiable space.