There are two classes of vessels which，to the extent necessary to carry out their work，do not have to comply with the rule regarding traffic separation schemes. One of these is a vessel（）.

A.provide routing and scheduling procedures to reduce shipping delays
B.provide traffic patterns in congested areas，so that vessels can operate without having a separate lookout
C.provide inbound and outbound lanes to promote the safe flow of vessel traffic
D.prohibit vessels carrying hazardous cargoes from entering waters that are environmentally sensitive

A.my entering
B.for my entering
C.for me to enter
D.I am entering

A.has
B.have
C.has been
D.have been