A tug in irons is（）.

A.tidal wave
B.storm surge caused by a hurricane or tropical storm
C.earthquake on the ocean's floor
D.tornado

A.is located between the scheme and the nearest land
B.separates traffic proceeding in one direction from traffic proceeding in the opposite direction
C.is designated as an anchorage area
D.contains all the traffic moving in the same direction

A.the chocks at the bow of a towed vessel
B.the most forward，centermost point of a towed vessel such as a sturdy bow rail
C.the mast of a towed sailboat
D.a secure fitting near the bow of the towed vessel