[求助]GWD-TN-11 Q3

T-3-Q3.
            

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.[TZJ1] 

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.[TZJ2] 

B.   
Whether the insecticides
typically used on ordinary cotton tend to be more expensive than insecticides
typically used on other crops.[TZJ3] 

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.[TZJ4] 

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.

我认为应该选D。题目说因为种植modified seed比ordinary seed贵而且没有产生更高市场价值的产量（yield通常都指产量），所以种modified seed对棉农来说不是经济上有益的。

D正好问了是不是因为种植ms的面积太小了导致产量低（进而导致成本高）呢？