You are creating an application that consumes a Windows Communication Foundation (WCF) service. The service implements the IService contract. The client application contains the CallbackHandler class, which implements IServiceCallback.You need to ensure t

You are creating an application that consumes a Windows Communication Foundation (WCF) service. The service implements the IService contract. The client application contains the CallbackHandler class, which implements IServiceCallback.You need to ensure that a client proxy is created that can communicate with the service over a duplex channel.Which code segment should you use?（）

A.

B.

C.

D.