单项选择题
The term restricted visibility，when used in the Rules，refers to（）.
A.Situations when you can see vessels on radar that you cannot see visually B.Visibility of less than half a mile C.Any condition where visibility is restricted D.Visibility where you cannot see shore
单项选择题 The term PROLONGED BLAST refers to（）.
单项选择题 The Rules state that risk of collision shall be deemed to exist（）．
单项选择题 The Rules state that a seaplane shall（）.
