【单选题】When your vessel is proceeding to the area of traffic density, ____ is used to determine the exact ranges of other ships or objects in the vicinity.
【单选题】When your vessel is proceeding to the area of traffic density, ___ _ is used to determine the exact ranges of other ships or objects in the vicinity
【单选题】When your vessel is proceeding to the area of traffic density _____is used to determine the exact ranges of other ships or objects in the vicinity.