Option b is the correct answer. The Dipavamsa and Mahavamsa both affirm the occurrence of the third Buddhist Council during Ashoka's rule. The third Buddhist Council was held in 250 BCE at Pataliputra in India, during the reign of the Mauryan emperor Ashoka. The council was presided over by Moggaliputta Tissa, and its main purpose was to purify Buddhism from heretical sects and practices. The council also compiled a definitive version of the Buddhist canon. Important Tips Dipavamsa: The Dipavamsa, Sri Lanka's earliest historical account, compiled around the 3rd to 4th century CE, along with Mahāvamsa, narrates ancient history of Sri Lanka and India. As a notable work in Buddhist and Pali literature, it highlights Buddha's visits, Tooth Relic's arrival, doctrine's spread, and Vijaya's arrival. Authored by monks or nuns from Anuradhapura Maha Viharaya, it omits Buddha's visit to Sri Pada. Mahavamsa: The Mahāvamsa, a meticulously preserved historical chronicle of Sri Lanka until Mahasena's era, is an epic poem in Pali. Covering legendary origins to Mahasena's reign, it was composed by a monk in Anuradhapura around the 5th century CE. In 2023, the Mahavamsa was listed an item of documentary heritage on the UNESCO's Memory of the World International Register. Divyavadana: The Divyāvadāna, a Sanskrit anthology, houses ancient Buddhist avadana tales, potentially from the 2nd century CE. It features the Buddha narrating how past actions shape present karma. A significant theme highlights the merits of offering to enlightened beings or holy sites. The anthology includes 38 stories, such as the well-known Aśokāvadāna. Translated by scholars like John Strong and edited by P. L. Vaidya, it encompasses stories like Rudrāyana-avadāna explaining the Buddha's illustration gift to King Rudrayana.