Each hand portable，semi-portable and fixed fire extinguishing unit on a ship must be tested and inspected at least once every（）.

A.the name of the unit on which it is located
B.the date that it was installed on the unit
C.the names of the individuals qualified to use it
D.an identification number different from other extinguishers on the unit

A.the pump discharge
B.the manifold connection
C.each fire station discharge
D.the pump station

A.American Petroleum Institute
B.National Standard Fire hose Coupling
C.American Society of Mechanical Engineers
D.Underwriter's Laboratories，Inc