单项选择题
（）the captain said is reasonable.
A.That B.It C.Which D.What
单项选择题 （）tankers over 100 meters long must not proceed beyond Dongbei Buoy.
单项选择题 International distress signal in VHF calling for help is（）.
单项选择题 There are salvage operations（）position 120.0N 12.5E.
