A.true meridian and the axis of the compass card B.true meridian and the magnetic meridian C.magnetic meridian and the axis of the compass card D.axis of the compass card and the degaussing meridian
A.vessel's geographic position B.vessel's heading C.earth's magnetic field D.influence of the magnetic materials of the vessel
A.deviation minus variation B.variation plus compass course C.combined variation and deviation D.difference between true and magnetic heading