In response to high mortality in area hospitals, surgery was restricted to emergency procedures during a five-week period. Mortality in these hospitals was found to have fallen by nearly one-third during the period. The number of deaths rose again when elective surgery (surgery that can be postponed) was resumed. It can be concluded that, before the five-week period, the risks of elective surgery had been incurred unnecessarily often in the area. Which one of the following, if true, most seriously undermines the conclusion above? ['The physicians planning elective surgery performed before the five-week period had fully informed the patients who would undergo it of the possible risks of the procedures.', 'Even if a surgical procedure is successful, the patient can die of a hospital-contracted infection with a bacterium that is resistant to antibiotic treatment.', 'The conditions for which elective surgery was performed would in the long run have been life-threatening, and surgery for them would have become riskier with time.', 'Elective surgery is, in general, less risky than is emergency surgery because the conditions requiring or indicating surgery are often less severe.']