You are using a radar in which your own ship is shown at the center，and the heading flash always points to 0°. If bearings are measured in relation to the flash，what type of bearings are produced?（）.

A.magnetism from the earth's magnetic field
B.misalignment of the compass
C.magnetism within the vessel
D.a dirty compass housing

A.deviation minus variation
B.variation plus compass course
C.combined variation and deviation
D.difference between true and magnetic heading

A.vessel's geographic position
B.vessel's heading
C.earth's magnetic field
D.influence of the magnetic materials of the vessel