B gives a comparison between cotton growers and other growers, however, the passage did not mention the farmers who grow othr crops. The conclusion of the passage is based on a comparison within the group who grow different cottons.
I feel E is better because E states that, if these farmers do not use new seeds, they would have to spend a lot more money on pestcide. Actually the new seeds helped them to save money.
题目的结论是Therefore, since the modified seed costs more than ordinary seed without producing yields of higher market value, switching to the modified seed would be unlikely to benefit most cotton farmers economically.
E是 Whether most of the farmers who tried the modified seed did so because they had previously had to use exceptionally large quantities of insecticide 即时试验的人需要大量的药物,也不能说明大部分种棉花的人也是这种状况