单项选择题
A.Directing the beam of a searchlight at another vessel
B.A smoke signal giving off orange colored smoke
C.A whistle signal of one prolonged and three short blasts
D.International Code Signal PAN spoken over the radiotelephone
单项选择题 A RADIO SIGNAL FROM A DISTRESSED VESSEL AUTOMATICALLY DIRECTED TO A RCC GIVING POSITION，IDENTIFICATION，COURSE AND SPEED OF THE VESSEL AS WELL AS THE NATURE OF DISTRESS is known as（）.
单项选择题 You receive a call from the MSA OF CHINA addressed to all stations. The call begins with the words Pan-Pan (3 times). Which type of emergency signal would this be?（）.
单项选择题 A continuous sounding of a fog-signal apparatus indicates（）.