Which river basin occupies the largest area in Bihar?

ihar falls within the Ganga River basin. The key to this question is the precise association expressed in its wording: “” The answer Ganga Basin matches that clue directly and is therefore factually appropriate. Option A — Son Basin — 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 — Kosi Basin — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. Option D — Gandak Basin — 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. Most of Bihar falls within the Ganga River basin.