单项选择题 A vessel is overtaking when she can see which light(s) of a vessel ahead?（）

单项选择题 A vessel is inclined at an angle of loll. In the absence of external forces，the righting arm (GZ) is（）.

单项选择题 A vessel is heading magnetic northwest and its magnetic compass indicates a heading of 317°. What action should be taken to remove this error during compass adjustment? （）