Option c is the correct answer. Nalanda University was famous in the world for Buddhist religious philosophy. It was a major center of learning in the Indian subcontinent from the 5th to the 12th centuries. The university attracted students from all over Asia, and its faculty included some of the most prominent scholars of the time. Nalanda was known for its teaching of Buddhist philosophy, but it also offered instruction in other subjects, such as mathematics, astronomy, and medicine.