Which of the following would it be most useful to know in evaluating the reasoning of the argument? A. Whether the drop in white blood cell count that occurs in rats under conditions of stress is sufficient to make the rats more susceptible to diseases that white blood cells normally combat. B. Whether normal white blood cell counts vary widely among healthy rats that are not under conditions of stress. C. Whether the adrenal glands of rats that are under conditions of stress increase production of any hormone other than corticosterone. D. Whether the adrenal glands of rats produce elevated levels of corticosterone on occasions when the rats are not under conditions of stress. E. Whether rats' adrenal glands are affected by hormones produced by any of the rats' other organs.