Correct Option: C. Sudan Detailed Explanation: Cotton is a significant cash crop in many countries, but its cultivation often requires specific climatic and agricultural conditions, particularly irrigation. In this context, let's analyze why Sudan is the correct answer and why the other options are less suitable.

1. Understanding Cotton Cultivation:
2. Cotton is a drought-sensitive crop that thrives in warm climates with adequate water supply. In regions where rainfall is insufficient, irrigation becomes essential to ensure a successful yield.
3. Countries that rely heavily on cotton production often have established irrigation systems to support this crop, especially in arid and semi-arid regions.
4. Sudan's Agricultural Economy:
5. Sudan has a long history of cotton cultivation, particularly in the Gezira Scheme, which is one of the largest irrigation projects in the world. This scheme utilizes water from the Blue Nile and White Nile rivers to irrigate vast areas of land specifically for cotton production.
6. Cotton is a major export product for Sudan, contributing significantly to the country's economy. The reliance on irrigation for cotton farming in Sudan makes it a cornerstone of the agricultural sector.
7. Analysis of Other Options:
8. A. Mali: While Mali does grow cotton, it primarily relies on rain-fed agriculture. The cotton sector in Mali is important, but it does not depend on extensive irrigation systems like those in Sudan. The climate in Mali is more variable, and while irrigation is used in some areas, it is not the mainstay of the agricultural economy.
9. B. Zimbabwe: Zimbabwe has a diverse agricultural sector, including cotton farming. However, cotton production in Zimbabwe is also largely rain-fed, and while irrigation is practiced, it is not as central to the economy as it is in Sudan. The country faces challenges such as economic instability and climate variability, which affect agricultural output.
10. D. Uganda: Uganda's agricultural economy is diverse, with crops like coffee, tea, and matoke being more prominent. Cotton is grown in Uganda, but it is not the mainstay of the agricultural economy, and irrigation is not as widespread or critical as in Sudan.
11. Conclusion:
12. The key factor that makes Sudan the correct answer is the extensive use of irrigation in cotton farming, which is vital for the crop's success in the region. The Gezira Scheme exemplifies how irrigation can transform agricultural practices and support a country's economy.

Revision Summary:

• Cotton requires irrigation in arid regions for successful cultivation, making it a cash crop in countries with established irrigation systems.
• Sudan's Gezira Scheme is a prime example of large-scale irrigation supporting cotton farming, making it central to the economy.
• Mali, Zimbabwe, and Uganda rely more on rain-fed agriculture for cotton, making them less dependent on irrigation compared to Sudan.
• Understanding the role of irrigation in agriculture is crucial for identifying key crops and their economic importance in different countries.