According to the Rules，when should lights be displayed?（）.

A.only the lights for a vessel towing
B.only the lights for a vessel restricted in her ability to maneuver
C.the lights for a towing vessel and the lights for a vessel restricted in her ability to maneuver
D.the lights for a towing vessel and the lights for a vessel not under command

A.towing vessel is less than 50 meters
B.towing vessel is greater than 50 meters
C.tow is less than 200 meters
D.tow is greater than 200 meters

A.A black ball in the forepart of her vessel
B.A black double frustum of a cone
C.A basket where best seen
D.A black cone point upwards