The magnetic compass magnets are acted on by the horizontal component of the Earth’s total magnetic force. This magnetic force is GREATEST at the（）.

A.compass north
B.the direction of the vessel's head
C.magnetic north
D.a relative bearing taken with an azimuth circle

A.always shows true north direction
B.indicates the vessel's heading
C.is always parallel to the vessel's transom
D.is located on the compass card

A.deviation
B.variation
C.compass error
D.dip