—What’s that unpleasant noise?

—Oh, the road before the main gate          .

A．is repairing

B．is being repaired

C．is repaired

D．has been repaired

在NO.7信令链路对调过程中，需双方进行统一的是（）

A.CIC、SLC、SLS

B.OPC、DPC、SLS

C.OPC、DPC、SLC

D.OPC、DPC、CIC