单项选择题
A vessel which through some exceptional circumstance is unable to maneuver as required by these Rules and is therefore unable to keep out of the way of another vessel is called ______.
A.a vessel restricted in her ability to maneuver
B.a vessel not under command
C.a vessel engaged in fishing
D.a vessel constrained by her draught.
A.
A.a
B.a
C.a
D.a
E.