Explanation
Banka is the answer that matches the Bihar-specific fact asked in the question. Option A — — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. It may be associated with another Bihar-related context, but that broader association does not satisfy this specific wording. Option B — — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. Option D — — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. Bihar GK questions frequently place neighbouring districts, related historical personalities, nearby rivers or institutions from the same field among the options. Banka district is known for lac production and forest-based activities. In ‘Which Bihar district is famous for lac production?’, the decisive clue is the exact place, institution, event, physical feature or administrative category mentioned in the stem. Bihar GK questions frequently place neighbouring districts, rivers, historical centres, personalities or government institutions together as distractors, so recognition of a familiar name alone is insufficient. The alternatives Jamui, Munger, Nawada may be valid Bihar-related terms, but they do not satisfy the complete relationship asked here.