单项选择题
A.four vessels are nearby
B.a vessel has a steady bearing at a constant range
C.there is any doubt that a risk of collision exists
D.a special circumstance situation is apparent
单项选择题 Power-driven vessels must keep out of the way of sailing vessels except（）.
单项选择题 On open waters，a vessel fishing is in a crossing situation with a vessel sailing located on the fishing vessel’s starboard side. Which vessel is the stand-on vessel?（）.
单项选择题 On open waters，a power-driven vessel shall keep out of the way of a（）.