The patrolman，while on duty on a passenger vessel，must have in his possession a(n)（）.

A.a helicopter carrying cargo only
B.a turbine-equipped helicopter
C.a Sikorsky
D.a helicopter carrying injured personnel in an emergency situation

A.in the midships house
B.at the main deck manifold
C.at the vent header
D.in the pumproom

A.corrosion
B.rough weather
C.defective sockets
D.mishandling