请教一道逻辑题

cx89916

Scientists have made genetic modifications to cotton to increase its resistance to insect pests. According to farmers’ report, the amount of insecticide needed per acre to control insect pests was only slightly lower for those who tried the modified seed than for those who did not. 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.
Which of the following would it be most useful to know in order to evaluate the argument?
A.    Whether farmers who tried the modified cotton seed had ever tried growing other crops from genetically modified seed.
B.    Whether the insecticides typically used on ordinary cotton tend to be more expensive than insecticides typically used on other crops.
C.    Whether for most farms who grow cotton it is their primary crop
D.    Whether the farmers who have tried the modified seed planted as many acres of cotton, on average, as farmers using the ordinary seed did.
E.    Whether most of the farmers who tried the modified seed did so because they had previously had to use exceptionally large quantities of insecticide.
GWD的题，答案选B，我有点不明白，如果insecticides used on ordinary cotton tend to be more expensive than insecticides used on modified seed, 那么我觉得就很好理解了，可是答案中的B让我不太明白，还请大牛们指教。谢谢~

yaffa

没有回复，可能是因为太难了。。。
不明白答案为什么是B。

2008115061

文章认为新品种小麦代价更大，但是能节约的化肥的量很少  所以是很不划算得。 但节约的量虽然不多，但有没有可能新品种小麦能用单价更便宜的化肥，从而更经济实惠？这就是要评估的