Answer : 4. "गंगानगर एवं हनुमानगढ़ "
Explanation :

1. Cotton is a tropical and subtropical bushy plant, whose height can range from 1.5 to 2 meters.

2. Many pods grow on this plant. In these pods, there is a fibre wrapped around the seeds. Clothes are prepared from this fibre. Its seeds are used as animal fodder.

3. Oil is also extracted from its seeds. After extracting the oil, the remaining part is also used as animal fodder and fertilizer.

4. The two major cotton-producing districts in Rajasthan are Ganganagar and Hanumangarh.