单项选择题
A cardinal mark showing an uninterrupted quick-flashing white light indicates the deepest water in the area is on the（）.
A.north side of the mark B.west side of the mark C.east side of the mark D.south side of the mark
单项选择题 A buoy，being a shape of cylinder and with red group flashing，shows that it is（）.
单项选择题 A buoy with a composite group-flashing light indicates a(n)（）.
单项选择题 A buoy marking a wreck will show a(n)（）.
