Final answer:
Wheeled service carts may be used but not stored in corridors if staff are trained to relocate them during an emergency, like a fire, to ensure corridors are not obstructed.
Step-by-step explanation:
The usage of wheeled food service or housekeeping carts in corridors must adhere to specific safety regulations to ensure that they do not obstruct emergency egress or contribute to fire hazards. The correct statement regarding this usage is: B. They may be used (but not stored) in corridors if staff are trained to relocate the carts during a fire.
This means that while carts can be temporarily present in corridors, they should not be left unattended or stored there to maintain clear passageways. In the event of an emergency, such as a fire, trained staff should know how to quickly and safely move these carts to prevent obstruction of the corridor, which would otherwise hinder the evacuation process and access by emergency responders.