Correct option is B
The sorghum + pigeonpea crop system is primarily practiced in rainfed upland areas, where irrigation is not available, and crops depend solely on rainfall.
Lowland upland system: This involves growing different crops in lowland (wet) and upland (dry) zones of the same field, often seen in paddy-based systems.
Interculture system: While sorghum and pigeonpea are often intercropped, the term "interculture system" focuses on agronomic management practices.
Mixed farming system: Refers to integration of crops and livestock on the same farm. Since this is purely a crop combination.