单选题A vessel aground at night is required to show two red lights in a vertical line as well as （）.A not under command lightsB restricted in her ability to maneuver lightsC anchor lightsD sidelights and a sternlight

A partly submerged vessel or object being towed，which is not readily noticeable，shall show ______.

A.yellow lights at each end

B.two red lights in a vertical line

C.a black ball

D.a diamond shape

A vessel not under command shall display ______.

A.two red lights at night and two black balls during daylight

B.two red lights at night and three black balls during daylight

C.three red lights at night and two black balls during daylight

D.three red lights at night and three black balls during daylight

An anchored vessel on pilotage duty must show which light(s) at night?

A.A sternlight only

B.Anchor lights only

C.A white light over a red light only

D.A white light over a red light and anchor lights

At sea you sight two red lights. This would indicate ______.

A.A vessel engaged in laying cable

B.A vessel not under command

C.A vessel launching and recovering aircraft

D.All of the above

A vessel not under command making way at night would show ______.

A.two all-round red lights in a vertical line

B.anchor lights and sidelights

C.two all-round white lights in a vertical line，sidelights and a stern light

D.two all-round red lights in a vertical line，sidelights，and a stern light

A vessel towing a barge astern would show，at the stern ______.

A.only a stern light

B.a towing light above the stern light

C.two towing lights in a vertical line

D.two white lights in a vertical line

Which vessel may show three lights in a vertical line，the top and bottom being red and the middle being white?

A.A vessel engaged in diving operations

B.A pilot vessel

C.A vessel trawling

D.All of the above