单项选择题
A.underway but not making way
B.making way，not under command
C.not under command，not making way
D.trolling underway
单项选择题 Two short blasts of the whistle have all of the following meanings EXCEPT（）.
单项选择题 Which vessel，when anchored at night，is NOT required to show anchor lights?（）.
单项选择题 While underway，in fog，you hear a whistle signal of one prolonged blast followed by two short blasts. This signal is sounded by a vessel（）.