单项选择题
A continuous sounding of a fog-signal apparatus indicates（）.
A.the vessel is in distress B.the vessel has completed loading dangerous cargo C.it is safe to pass D.the vessel is anchored
单项选择题 All of the following are distress signals EXCEPT（）.
单项选择题 All of the following are distress signals under the Rules EXCEPT（）.
单项选择题 What is NOT a distress signal?（）.
