单项选择题
A.radio communications that are available
B.maximum speed of your vessel
C.temperature
D.current
单项选择题 The rules require that a stand-on vessel SHALL take action to avoid collision when she determines that（）.
单项选择题 The risk of collision shall be deemed to exist if the compass bearing of an approaching vessel （）.
单项选择题 The effectiveness of the action shall be carefully checked until the other vessel is finally （）.