单项选择题
A.When at anchor，the pilot vessel is only required to sound anchor signals
B.The identification signal must be sounded any time the pilot vessel is underway
C.The pilot vessel may only sound the identity signal when making way
D.All of the above
单项选择题 Concerning a celestial observation，the azimuth angle is measured from the principal vertical circle to the（）.
单项选择题 Compliance with the terms of the load line certificate on a ship is the responsibility of the（）.
单项选择题 Complete information on weather broadcasts throughout the world is contained in（）.