单项选择题
Deviation which is maximum on intercardinal compass headings may be removed by the（）.
A.Flinders bar B.transverse magnets C.fore-and-aft magnets D.soft iron spheres on the sides of the compass
单项选择题 Deviation is the angle between the（）.
单项选择题 Deviation in a compass is caused by the（）.
单项选择题 Compass error is equal to the（）.
