Which of the following would it be most useful to establish in order to evaluate the argument? A. Whether Sordane is the most effective pesticide available to farmers in Fillmore County B. Whether, as a result of last year's spraying of Sordane, this year's population of harmful insects was smaller than it would have been in a year following one in which fanners used only Kaskanine C. Whether the increase in the incidence of respiratory illness in Fillmore County caused by aerial spraying of Sordane was the only consideration in the farmers' decision to switch to Kaskanine D. Whether the use of Sordane has been discontinued in other counties for the same reasons as in Fillmore County E. Whether restrictions on the use of Sordane could have produced a significant reduction in the incidence of respiratory illness