The correct option is C Nalanda
Nalanda, a large Buddhist monastery, now in ruins, was one of the most publicly acknowledged Mahaviharas of ancient India located in ancient Magadha kingdom (modern Bihar). It remained a learning centre from 7th century BCE through c. 1200 CE and is many a time categorised as one of the early universities of India along with other institutions like Vikramashila and Taxila. Pilgrims like Hu-en-Tsang, and others spent time studying in Nalanda (Bihar) the most famous Buddhist monastery of the period.