单项选择题
The compass deviation changes as the vessel changes（）.
A.geographical position B.speed C.heading D.longitude
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（）.
单项选择题 Magnetic variation changes with a change in（）.
