Litchi — option 3, as recorded in the Commission’s key.

Bihar and litchi. The crop is concentrated with unusual tightness in one belt of the state — Muzaffarpur above all, with Vaishali, East Champaran, Samastipur and Begusarai — and Bihar dominates Indian production. The variety is the famous Shahi litchi, which received a Geographical Indication tag in 2018 for its aroma, its small seed and its high pulp content; China, Bihar’s only real rival, grows different varieties.

Why the belt is so concentrated. Litchi is a demanding tree: it needs deep, well-drained calcareous alluvial soil, high humidity in summer, a cool dry winter to set flower buds, and freedom from hot dry winds at fruiting. The Gandak plain of north Bihar supplies exactly that combination, and few other parts of India do.

The problem of the crop. The fruit is extremely perishable: it loses its colour within a day or two of picking and will not keep. That, and the three-week season, are why so much of the crop is sold locally at low prices, why cold storage and air freight matter so much to the trade, and why processing into pulp, juice and dried litchi has been a policy priority.

Where the other fruits belong : pineapple in the north-east and Kerala, orange in Nagpur and in the north-east, mango most of all in Uttar Pradesh and Andhra Pradesh — though Bihar’s Jardalu mango of Bhagalpur carries a GI tag of its own.

Hence, the answer is Lychee.