单项选择题
A.the masthead lights for a towing vessel
B.the lights for a vessel restricted in its ability to maneuver
C.sidelights，sternlight and towing light
D.All of the above
单项选择题 A vessel is equipped with a single right-handed screw. With rudder amidships and calm wind，the vessel will most likely back（）.
单项选择题 A vessel is considered to be restricted in her ability to maneuver under the Rules if she is （）.
单项选择题 A vessel fitted with twin screws is easier in（）than a vessel with single screw.