单项选择题
A vessel sighting a northern right whale dead ahead should（）.
A.maintain course and speed B.alter course to give a wide clearance C.report the whale's position to the Canadian Coast Guard D.All of the above
单项选择题 A vessel showing a rigid replica of the International Code flag “A” is engaged in（）.
单项选择题 A vessel showing a green light over a white light in a vertical line above the level of the sidelights is（）.
单项选择题 A vessel servicing a pipeline during the day shall display（）.
