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.

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.