A plane perpendicular to the polar axis will never form what line on the Earth’s surface? （）

单项选择题A parallel of latitude other than the equator is a（）.

A.great circle
B.loxodromic curve
C.small circle
D.gnomonic curve

单项选择题A nun buoy will（）.

A.be green in color
B.have an even number
C.be left to port when entering from seaward
D.be cylindrical in shape

单项选择题A mid-channel buoy，if lighted，will show a（）.

A.fixed red light
B.Morse (A) white light
C.green light
D.flashing red light

单项选择题A line on the Earth parallel to the equator is a（）.

A.gnomonic curve
B.small circle
C.meridian
D.great circle

单项选择题A line of position formed by sighting two charted objects in line is called a(n)（）.

A.relative bearing
B.range line
C.track line
D.estimated position