ATT （Attached ）bit needs to be set in the link state PDUs in an IS-IS level-1-2 router to indicate that theyare a potential exit point out of the area.（）

A.Bandwidth that is reserved for SVCs to route over a trunk
B.Bandwidth that is reserved on a trunk so that ABR connections can burst
C.Bandwidth on a trunk that is reserved for control traffic and cannot be used by connections
D.Bandwidth that cannot be allocated to connections but can be used to accommodate statistical variations in the traffic

A.Tag Calling Interface
B.Tag Control Identifier
C.ToS Class Interface
D.Tag Control Information

A.normal
B.discard
C.random
D. full