Your vessel has been damaged and is taking on water，but you do not require immediate assistance. You would preface a message advising other vessels of your situation with（）.

The urgency signal concerning the illness of persons on...

单项选择题The urgency signal concerning the illness of persons on board ship is（）.

If you wished to transmit a message by voice concerning...

单项选择题If you wished to transmit a message by voice concerning the safety of navigation，you would preface it by the word（）.