Out of those suffering from manic depression, patients who l

Out of those suffering from manic depression, patients who live at home have more bouts of depression than do patients at mental health care facilities. To test the hypothesis that the stress-free environment of such facilities is the sole reason for their success, some recently-diagnosed patients were relocated to a mental health care facility and others were studied in their home environments, from which stress-causing factors had been eliminated. It was found that both groups had an equal number of depression bouts.

The answer to which of the following questions would contribute the most to understanding the significance of the experiment results in relation to the hypothesis tested?

a. Whether most of the patients observed in the home environments were living with family members.
b. Whether there were some patients in the health care facility who would have preferred to remain in their home environments.
c. Whether the doctors observing patients in their home environments were more accredited than the doctors observing the other group.
d. Whether the dosage of anti-depressive medicine was the same for patients in both the groups studied.
e. Whether the time period of study was sufficient for patients to acclimatize to new surroundings that could otherwise have caused severe anxiety.

OA: E

What's wrong with options B and D?