单项选择题
A.in a crossing situation
B.in a meeting situation
C.when they are the overtaking vessel
D.on the inland waters of the PR China
单项选择题 Risk of collision is considered to exist if（）.
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?（）.