請依下文回答第 46 題至第 50 題    Since occupants of an office building can be expected to be familiar with their environment, have less delay instarting their evacuation, and are generally more mobile and able bodied, they will likely take less time to reachprotected exits. Therefore, an office building smoke control system might be limited to active systems to protect itsstairways and passive means to protect floor-to-floor smoke spread. If, however, the same office building has highoccupant loads per floor or the building includes assembly or dining at the top floor(s), or there is a simultaneousevacuation of numerous floors resulting in longer evacuation times due to queuing, the additional analysis may benecessary to determine whether additional active or passive smoke control measures are necessary.
46 Why do the staff in the office buildings have more available time in starting their evacuation?
(A)Because they are younger
(B)Because they know where they are
(C)Because they have frequent fire drills
(D)Because the detection and alarm systems activate normally