The correct answer is option 2, 261 BC. The Kalinga war took place during the Mauryan dynasty. It was a major conflict between the Mauryan Empire, led by Emperor Ashoka, and the kingdom of Kalinga, which is located in present-day Odisha, India. The war occurred in the year 261 BC. This war is significant because it had a profound impact on Emperor Ashoka. The brutal violence and loss of life in the war deeply affected him, leading to a change in his policies and beliefs. After witnessing the horrors of war, Ashoka renounced violence and embraced Buddhism, advocating for peace and spreading the teachings of the Buddha throughout his empire.