The correct answer is: Buddhist learning.
Nalanda was an ancient Indian university located in the Nalanda district of the Indian state of Bihar. The site is a UNESCO World Heritage Site. Nalanda was a Mahavihara, a large Buddhist monastery, teaching both Buddhist and secular subjects. The university was established in the 5th century CE, and flourished under the patronage of the Gupta Empire. It was destroyed by the Muslim invaders in 1197 CE.
Nalanda was a renowned center of Buddhist learning. It attracted students from all over Asia, including China, Korea, and Japan. The university had a large library, which was said to contain over 9 million manuscripts. Nalanda was also a center of Buddhist art and architecture.
The other options are incorrect. Jain philosophy is a system of thought that emphasizes non-violence and compassion. Hindu scriptures are the sacred texts of Hinduism. Greek studies is the study of the language, literature, and history of ancient Greece.