The midships house of your break bulk ship is constructed with an interior stairtower from the main deck to the bridge. Under what circumstances may the doors from each deck to the stairtower be kept open when underway?

A
They may be kept open if they can be automatically closed from the bridge.
B
They are to be kept closed at all times.
C
They may be kept open if the ventilation or air conditioning system is shut down.
D
They can be kept open if the station bill has personnel designated to close them in case of fire.
E