Which famous fair held in Bihar is considered one of Asia's largest cattle fairs?

Asia's largest traditional cattle fairs. The key to this question is the precise association expressed in its wording: “Which famous fair held in Bihar is considered one of Asia's largest cattle fairs?” The answer Sonepur Fair matches that clue directly and is therefore factually appropriate. Option A — Rajgir Fair — 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 — Pitrapaksha Fair — is incorrect because it does not match the exact person, district, location, institution, river, event or identifying feature required by the question. Option D — Mandar Fair — 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. Sonepur Fair is among Asia's largest traditional cattle fairs.