Which river is often called the 'Sorrow of Bihar' due to frequent floods?

ecause of its devastating floods. The key to this question is the precise association expressed in its wording: “Which river is often called the 'Sorrow of Bihar' due to frequent floods?” The answer Kosi matches that clue directly and is therefore factually appropriate. Option A — Bagmati — 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 C — Son — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. Option D — Punpun — 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. The Kosi River is called the Sorrow of Bihar because of its devastating floods.