Regarding coffee's effectiveness on memory amongst those who do not display "sensitivities to caffeine," the author assumes that A. more rigorous analysis in the form of follow up studies must be conducted B. the researchers must be more forthcoming in their findings C. this group displayed a uniform tendency D. any positive effects will be negated by the effects exhibited by those with sensitivities to caffeine E. this effectiveness was fleeting, and tended to all but disappear within a week of the study