单项选择题
A.Engaged in fishing B.Mine sweeping C.A pilot boat D.Under sail
A.To avoid immediate danger B.When authorized by the rig superintendent C.To comply with an operator's requirement D.Under no conditions
A.alter course to starboard and pass port to port B.alter course to port and pass starboard to starboard C.decide on which side the passage will occur by matching whistle signals D.slow to bare steerageway