单项选择题
A.decrease speed
B.increase speed
C.turn to port for a vessel on her own port side
D.turn to starboard for a vessel on her own port side
单项选择题 Any vessel（）any other shall keep out of the way of the vessel（）.
单项选择题 Any alteration of course and／or speed to avoid collision shall，if the circumstances of the case admit，（）to another vessel observing visually or by radar.
单项选择题 All of the following constitute special circumstances EXCEPT（）.