Option c is the correct answer. During the Mauryan period, the most renowned center of learning was Taxila. This ancient university, situated near the Indus River in present-day Pakistan, offered education in religious and secular subjects. Initially focused on Brahmanical teachings, it later became a hub for Buddhist scholarship. Taxila's influence extended across diverse fields like Vedic studies, astronomy, medicine, and more. Despite lacking formal colleges, it attracted eminent teachers like Pāṇini and Chanakya. Its prominence declined around the 5th century CE due to factors like Toramana's destruction, leaving behind a significant legacy in ancient education. Important Tips Vaishali: Vaishali, an ancient city in Bihar, India, is renowned for being a significant center during the 6th century BCE Vajjika League. Gautama Buddha delivered his last sermon here in 483 BCE, and the Second Buddhist Council was held in 383 BCE. The city is known for its association with both Jainism and Buddhism, featuring well-preserved relics, stupas, and monuments. Nalanda: Nalanda Mahavihara, located in ancient Magadha (modern Bihar), was a renowned Buddhist monastic university, considered the world's first residential university. Active from 427 to 1197 CE, it flourished during the Gupta Empire, teaching various Buddhist schools, Vedas, grammar, medicine, logic, and more. The site influenced East Asian Buddhism and remains a UNESCO World Heritage Site. Ujjain: Ancient Ujjain, an important center during Mauryan and Gupta periods, was a commercial hub on trade routes, fostering intellectual learning among Jain, Buddhist, and Hindu traditions. Kalidasa and Bharthari, renowned poets, wrote here. The Mahakaleshwar Jyotirlinga temple and Ujjain's rich history are notable, even visited by Xuanzang.