我不知道这道题是GWD那一套里的。

Q3:

Scientists have made genetic modifications to increase its resistance to insect pest.

According to farmers’ reports, the amount of insecticide needed per acre to control insect pest was only slightly lower for those who tried the modified seed than for those who did not. Therefore, since the modified seeds cost 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 be most useful in evaluating the argument?

B. whether the insecticides typically used on ordinary cotton tend to be more expensive than insecticides typically used on other crops.

什么样的逻辑关系？