单项选择题
A.Separation of opposing streams of traffic by separation zones or lines
B.The separation of through traffic from local traffic by provision of inshore traffic zones
C.Division of traffic from several different direction into sectors
D.Control of routing traffic through shipping routes
单项选择题 （） is a circular traffic lane used at junctions of several routes，within which traffic moves counterclockwise around a separation point or zone.
单项选择题 （） is a defined area within which ships must use particular caution and should follow the recommended direction of traffic flow.
单项选择题 When using a buoy as an aid to navigation which of the following should be considered?（）