问题：

[单选] 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 berth