The correct option is B centres of learning
Nalanda, Kashi and Vikramashila were well known centres of learning. Nalanda is one of the well-known ancient universities of India. Nalanda is located in the Indian state of Bihar, about 55 miles south-east of Patna, and was a Buddhist center of learning from 427 to 1197 CE. It has also been called “one of the first great universities in recorded history. Sarnath monastery on the outskirt of Benaras became a famous centre of learning under the patronage of Magadha king Ashoka. Vikramashila was one of the two most important centres of learning in India during the Pala Empire, along with Nalanda.