Option c is the correct answer. The Rashtrakuta rulers built the Ellora and Elephanta caves by cutting the walls of high basalt rock. The Ellora caves are a group of 34 monasteries and temples that reflect the religious diversity of ancient India, as they are dedicated to Buddhism, Hinduism, and Jainism. The Elephanta caves are a series of rock-cut cave temples that are mostly devoted to Shiva. Both sites are UNESCO World Heritage Sites and display remarkable artistic and architectural achievements.