Which statement about the hospital space on a cargo ship is TRUE（）.

A.The hospital may be used for disciplinary confinement if it is not being used for treatment
B.The hospital space must have both a bathtub and shower
C.A hospital is required on all vessels with a crew of 12 or more if it makes overnight voyages
D.If a ship has a crew of forty-five who do not have their own room，the hospital must have four berths