Ashoka is the answer that matches the Bihar-specific fact asked in the question. Kalinga War because the conquest caused death, deportation and widespread suffering. He subsequently presented dhamma-vijaya—conquest through ethical influence—as superior to aggressive military conquest and expanded measures for public welfare and moral conduct. The wording is deliberately precise: Ashoka’s Buddhist inclination may have begun before the war, but Kalinga clearly became the turning point in his publicly stated imperial policy. Option A, Bindusara, is incorrect because he was Ashoka’s father and ruled before the Kalinga War associated with Ashoka. Option B, Chandragupta Maurya, is incorrect because he founded the Mauryan Empire much earlier and Jain tradition, not the Kalinga edicts, is linked with his later religious life. Option D, Dasharatha, is incorrect because he was Ashoka’s grandson and successor; he did not fight the famous Kalinga War. Thus contemporary inscriptional evidence identifies Ashoka. Emperor Ashoka adopted Buddhism after witnessing the destruction caused by the Kalinga War. The alternatives Bindusara, Chandragupta Maurya, Dasharatha may be valid Bihar-related terms, but they do not satisfy the complete relationship asked here. A sound method is to identify the subject area first—geography, history, polity, economy or culture—and then verify the location, period and function separately. Revise the complete pair ‘Which Mauryan ruler renounced aggressive warfare and gave greater emphasis to dhamma after the Kalinga War? — Ashoka’ rather than an isolated option letter.