单项选择题
（）is not contained in the NM Weekly.
A.Amendments to Admiralty Sailing Directions B.Amendments to Admiralty List of Lights and Fog Signals C.Amendments to Admiralty List of Radio Signals D.Supplement to Guide to Port Entry
单项选择题 （）are published for the correction of Admiralty Charts．
单项选择题 A chart has extensive corrections to be made to it. When these are made and the chart is again printed，the chart issue is a （）.
单项选择题 Charts are subject to frequent correction according to （）.
