单项选择题
The maximum distance at which a light may be seen under the existing visibility conditions is called（）.
A.nominal range B.luminous range C.charted range D.geographic range
单项选择题 The luminous range of a light takes into account the（）.
单项选择题 Restricted areas at locks and dams are indicated by（）.
单项选择题 Preferred channel buoys indicate the preferred channel to transit by（）.
