The Most Important Reason That the Blood Collector's Tray Should

The most important reason that the blood collector's tray should not be carried into the room of a patient in isolation is that:

A) surfaces on the tray may act as a reservoir for infectious agents.
B) there is often no spare space available in an isolation room.
C) the tray should be left in the hallway so others may find the blood collector when needed.
D) supplies may be stolen from the tray.