In the Uniform Cardinal System of Buoyage， a buoy in the eastern quadrant from a danger could（）.

In the Uniform Cardinal System of Buoyage， a buoy in the eastern quadrant from a danger could（）.
A.be black and white horizontally striped
B.be black and white vertically striped
C.have a black top mark
D.be any of the above
正确答案：have a black top mark