Misrile, a tiny nation with extreme aridity, has surprised global agricultural community by developing a thriving citrus fruit industry. By using the nation's scarce supply of fresh water with maximum efficiency, farmers did the unthinkable. However, as the water demands of Misrile's growing population increases, the nation will inevitably need to import water from neighboring countries in order to maintain a thriving citrus fruit industry.
Which of the following is an assumption upon with the conclusion is based?
A. As water supplies in Misrile become tighter, the export price of its citrus fruits will increase, thereby justifying the expenditure of importing water.
B. Misrile cannot substantially increase its domestic supply of water by opening new desalinization plants on its coasts.
C. Neighboring nations are equally arid and will not export water to Misrile at a reasonable cost.
D. The people of Misrile can decrease the need for importing water by becoming more efficient in their use of water.
E. The best economic use of Misrile's land and scarce water supplies is to grow citrus fruits


I went with E but some of the user responses on the forum has been B

Source: another gmat forum


Guys/gals please chip in your thoughts.

Regards,
CR