单项选择题
What is the significance of the broken magenta lines which roughly parallel the shore between Roanoke Point and Orient Point on Long Island（）.
A.They mark the limits of breakers in that area B.These lines warn the mariner of submerged rocks C.They mark the boundary lines of fish trap areas D.These lines warn the mariner of submerged pipelines
单项选择题 What is the most important source of information to be used in correcting charts and keeping them up to date（）.
单项选择题 Weekly Notices are dated for the（）appropriate to the week they are issued on the UKHO website.
单项选择题 Weekly NMs are available without subscription from appointed（）.
