Which of the following, if true, best calls into question the conclusion of the argument? A. Neither the patients nor the doctors in either group (the control group or the Freloxamine group) knew which drug they were receiving. B. Since patients in both groups were briefed on the potential side effects of SSRI, which can often be pronounced, many in the Freloxamine group, upon exhibiting side effects, concluded that they were being administered the SSRI. C. Freloxamine does not exhibit a uniform effect in all patients, with many reporting little improvement in symptoms of depression, even after several months of taking the drug. D. At dosages two-fold of those employed in the trial, Freloxamine has been shown to cause brief episodes of psychosis. E. One subject from the Freloxamine group experienced debilitating side effects and was forced to drop out of the trial before its completion.