A.shown below the sternlightB.white in colorC.displayed……

单项选择题A towing light is（）.

A.shown at the bow
B.white in color
C.shown in addition to the sternlight
D.an all-round light

单项选择题A towing light（）.

A.flashes at regular intervals of 50-70 flashes per minute
B.is yellow in color
C.shows an unbroken light over an arc of the horizon of not less than 180°nor more than 225°
D.All of the above

单项选择题A signal of one prolonged，one short，one prolonged，and one short blast，in that order is given by a vessel（）.

A.engaged on pilotage duty
B.in distress
C.at anchor
D.being overtaken in a narrow channel

单项选择题A signal of intent must be sounded in international waters by（）.

A.a vessel meeting another head-on
B.a vessel overtaking another in a narrow channel
C.a vessel crossing the course of another
D.the give-way vessel in a crossing situation

单项选择题A sailing vessel shall not impede the safe passage of a（）.

A.power-driven vessel following a traffic lane
B.pilot vessel enroute to a pilot station
C.law enforcement vessel
D.All of the above