（）is not a position-fixing system.

A.Aero light
B.Radar station
C.Radar transponder beacon
D.Radiobeacon

A.the meridian through the object of the bearing
B.the meridian through the ship's position
C.the meridian midway between the ship and the object
D.any meridian

A.a straight line drawn on the chart approximates a great circle
B.the chart should not be used outside of the standard parallels
C.the course angle is measured at the mid-longitude of the track line
D.distance cannot be measured directly from the chart