单项选择题 When using a Lambert conformal chart in high latitudes，angles such as bearings are measured in reference to （）.

单项选择题 When navigating in high latitudes and using a chart based on a Lambert conformal projection，（）.

单项选择题 When a buoy is in position only during a certain period of the year，where may the dates when the buoy is in position be found?（）