The fourth Buddhist Council was held at

The correct answer is: A. Pataliputra

The Fourth Buddhist Council was held in Pataliputra, India, in 29 BCE. It was convened by Emperor Ashoka the Great, who invited Buddhist monks from all over India to attend. The council was called to discuss and resolve differences in the Buddhist teachings, and to codify the Buddhist scriptures. The council also produced a new set of rules for the monastic order.

The council was a major event in the history of Buddhism, and its decisions have had a lasting impact on the religion. The council’s teachings are still studied and practiced by Buddhists today.

The other options are incorrect because:

• Option B, Vaishali, was the site of the Second Buddhist Council.
• Option C, Kundalavana, was a monastery in Sri Lanka where the Third Buddhist Council was held.
• Option D, Bodh Gaya, is the site of the Bodhi Tree, under which the Buddha attained enlightenment.