单项选择题
The compass error of a magnetic compass that has no deviation is（）.
A.zero B.equal to variation C.eliminated by adjusting the compass D.constant at any geographical location
单项选择题 The compass deviation changes as the vessel changes（）.
单项选择题 Quadrantal error in a gyrocompass has its GREATEST effect（）.
单项选择题 Magnets are placed in horizontal trays in the compass binnacle to compensate for the（）.
