单项选择题
International Navtex service means the coordinated broadcast and automatic reception on（）khz of maritime safety information by narrow-band direct-printing telegraphy using English language.
A.518 B.2182 C.156.8 D.2187.5
单项选择题 Every ship constructed on or after（）shall comply with all the applicable requirements of this chapter.
单项选择题 In case a ship is in emergency or distress in any of 4 areas, it is required to use the continuous（）alert.
单项选择题 Radio beacon can be activated（）in case of distress.
