Which information must automatic identification systems (AIS) automatically provide to appropriately equipped shore stations，vessels and aircraft? （）

单项选择题When should the emergency position-indicating radiobeacon be activated after abandoning a ship?（）

A.Immediately
B.After one hour
C.Only when another vessel is in sight
D.Only after sunset

单项选择题When may the automatic identification system (AIS) be switched off? （）

A.At anytime as long as it is properly logged
B.At the Master's professional judgment
C.Only when the vessel is at anchor or in port
D.Under no circumstance

单项选择题When communicating on the radiotelephone using plain English，what procedure word indicates the end of my transmission and that a response is necessary? （）

A.Out
B.Over
C.Roger
D.Wilco

单项选择题To reduce the amount of catenary you may（）.

A.shorten the hawser or increase the tug's speed
B.lengthen the hawser or reduce the tug's speed
C.place your tug in irons
D.make a sharp turn

单项选择题The Vessel Bridge-to-Bridge Radiotelephone Act applies to which towboat?（）

A.A 100 GT towboat，24 feet in length
B.A 90-foot towboat tied to the pier
C.A 60-foot towboat towing by pushing ahead
D.A 400 GT towboat anchored