Answer: Three
Notes: According to the soil quality and climatic conditions of the relevant areas, Bihar has been classified in 3 agro-climatic zones : North-West Alluvial Plane ( Zone1), North-East Alluvial Plane ( Zone 2), and South Alluvial Plane (Zone 3). Zone 3 has been further classified in two sub-zones 3A and 3B. Monsoon arrives earliest in the northeastern Zone 2, which also receives the highest rainfall among all three zones. Zone 3 receives monsoon showers last of all three zones and also the least amount; and so is drought prone.
