A state in India has the following characteristics: 1) Its northern part is arid and semiarid. 2) Its central part produces cotton. 3) Cultivation of cash crops is predominant over food crops. Which one of the following states has all of the above characteristics ?

The answer is Gujarat. All three clues point to it together. The northern districts, such as Kutch, Banaskantha, Patan and parts of Mehsana, are arid and semi-arid, with Kutch bordering the Thar. The central belt around Ahmedabad, Surendranagar and Vadodara has black cotton (regur) soil and is the core of the state's cotton tract. Cash crops like cotton, groundnut and tobacco dominate the cropping pattern over food grains, which is the third clue.

• Andhra Pradesh: Its arid zone is Rayalaseema in the south, and the coastal delta is rice-dominated, so the north-arid and central-cotton pattern does not fit.
• Karnataka: North Karnataka is semi-arid and does grow cotton, but ragi, jowar and pulses still occupy more area than cash crops overall.
• Tamil Nadu: Rice and other food crops dominate, and it has no cotton-belt central zone of this kind.

Concept: dryland agriculture and regional cropping patterns, which links to Mains questions on Bt cotton, the Narmada canal network and the MSP and marketing problems of cash crops.

Trap: candidates pick Karnataka or Andhra because they have dryland areas, and forget the third clue that cash crops must dominate food crops.