单项选择题
A.In doubt that another vessel is taking sufficient action to avoid a collision
B.Altering course to starboard
C.Altering course to port
D.The stand-on vessel and will maintain course and speed
单项选择题 Every vessel which is directed by these Rules to keep out of the way of another vessel shall，if the circumstances of the case admit，avoid（）.
单项选择题 Every vessel which is（）to keep out of the way of another vessel shall，so far as possible，take early and substantial action to keep well clear.
单项选择题 Every vessel shall（）maintain a proper look-out by sight and hearing as well as by all available means appropriate in prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.