Option 1 -> The Takshila Battle was not a transformative event; Ashoka served as viceroy in Takshila but no major battle there changed his outlook.
Option 2 -> The Kalinga War (261 BCE) resulted in massive bloodshed with over 100,000 deaths, which deeply traumatized Ashoka and led to his spiritual awakening.
Option 3 -> The Battle of Buxar (1764 CE) occurred nearly 2000 years after Ashoka and involved the British East India Company, not Emperor Ashoka.
Option 4 -> The Battle of Ujjain was where Ashoka was injured and met his first wife, but it wasn't the catalyst for his spiritual transformation.
Hence, Option 2: The Kalinga War -> The unprecedented violence and suffering witnessed during the Kalinga War filled Ashoka with deep remorse. The sight of the battlefield covered with corpses and the cries of the wounded led him to renounce warfare and embrace Buddhism, dedicating his life to spreading the message of peace, non-violence (ahimsa), and Dhamma throughout his empire -> correct