单项选择题
A.maximum horsepower of your vessel
B.presence of background lights at night
C.draft of your vessel
D.maneuverability of your vessel
单项选择题 When a vessel sees the other ahead or nearly ahead，by night she could see the masthead lights of the other in a line or nearly in a line or both side lights，（）shall be deemed to exist.
单项选择题 When in sight of another vessel，any action taken to avoid collision must（）.
单项选择题 When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision，they shall be deemed to be in（）.