单项选择题
A.In master's cabin
B.In third office's cabin
C.In a break-glass-type enclosure conspicuously located adjacent to the room
D.In a locked locker conspicuously located adjacent to the room
单项选择题 Your vessel is crossing a narrow channel.A vessel to port is within the channel and crossing your course.She is showing a black cylinder.What is your responsibility?（）
单项选择题 The disinfection of various compartments in a vessel by filling with a gaseous agent to destroy rats and all insects pests which act as germ carriers means（）.
单项选择题 Backing means the wind（）.