有一道不懂GWD

Q21:
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 farmers 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

答案是B，不太明白和other crops 有什么关系~

要evaluate的是：换用价格高基因改良的种子和价格低但需要多一些农药的种子哪一种更划算。

A other corps的改良种子和比较无关

B如果这种农药用的比一般的贵，则可考虑换用更便宜的农药

C irrelevent

D 是否种更多也无关。