The correct answer is (b). Adhai Din ka Jhopra is a mosque in Ajmer, Rajasthan, India. It was built by Qutb-ud-din Aibak in 1199 AD, shortly after the Muslim conquest of India. The mosque is named after the fact that it was built in two and a half days. It is one of the oldest mosques in India and is a fine example of early Islamic architecture.
The other options are incorrect. Delhi is the capital of India and is located in the northern part of the country. Hyderabad is the capital of Telangana and is located in the southern part of the country. Agra is a city in Uttar Pradesh and is famous for the Taj Mahal.