分娩机制

Auditor from Acme Industries: Last week at Acme Bakery, about six percent of the pastries baked during the night shift were found to be imperfect, but no imperfect pastries were found among those baked during the day shift. Pastries are inspected during the same shift in which they are baked, so clearly the night-shift quality control inspectors were more alert, despite their nighttime work hours, than the dayshift quality control inspectors.
The argument depends on the assumption that

A．at least some imperfect pastries were baked during the day shift at Acme Bakery last week.

B．not all of the pastries that the night-shift quality control inspectors judged to be imperfect were in fact imperfect.

C．the night-shift quality control inspectors received more training in quality control procedures than did the day shift quality control inspectors.

D．in a normal week, fewer than six percent of the pastries baked during the night shift at Acme Bakery are found to be imperfect.

E．(E) there are only two shifts per day at Acme Bakery, a day shift and a night shift.