单项选择题
Which one of two crossing power-driven vessels has the right of way in a fog（）.
A.Both vessels B.Neither vessel C.The vessel on portside D.The vessel on starboard side
单项选择题 Which one of the following rules is not regarding two power-driven vessels meeting end or nearly end on so as to involve risk of collision（）.
单项选择题 Which display indicates a vessel conducting mineclearance operations（）.
单项选择题 When you doubt the existence of risk of collision,（）.
