单项选择题
A.from a submarine on the surface
B.the light at Southeast Point
C.at an airport
D.on a coastal patrol vessel
单项选择题 Fishing stake，the position of which frequently（），exist in the area covered by this chart.
单项选择题 Except for N-S courses，and E-W courses on the equator，a great circle track between two points，when compared to a rhumb line track between the same two points，will（）.
单项选择题 Buoys which only mark the left or right side of the channel will never exhibit a light with which characteristic? （）