A Windows Communication Foundation (WCF) service implements a contract with one-way and request-reply operations.
The service is exposed over a TCP transport. Clients use a router to communicate with the service.
The router is implemented as follows. (Line numbers are included for reference only.)

01 ServiceHost host = new ServiceHost(typeof(RoutingService));
02 host.AddServiceEndpoint(
03 typeof(ISimplexDatagramRouter),
04 new NetTcpBinding(), “net.tcp://localhost/Router”
05 );
06 List<ServiceEndpoint> lep = new List<ServiceEndpoint>();
07 lep.Add(
08 new ServiceEndpoint(
09 ContractDescription.GetContract(
10 typeof(ISimplexDatagramRouter)
11 ),
12 new NetTcpBinding(),
13 new EndpointAddress(“net.tcp://localhost:8080/Logger”)
14 )
15 );
16 RoutingConfiguration rc = new RoutingConfiguration();
17 rc.FilterTable.Add(new MatchAllMessageFilter(), lep);
18 host.Description.Behaviors.Add(new RoutingBehavior(rc));

Request-reply operations are failing. You need to ensure that the router can handle one-way and request-reply operations.
What should you do?

A.
Change line 03 as follows:
typeof(IRequestReplyRouter),

B.
Change line 03 as follows:
typeof(IDuplexSessionRouter),

C.
Change line 10 as follows:
typeof(IRequestReplyRouter)

D.
Change line 10 as follows:
typeof(IDuplexSessionRouter)

Explanation:
IDuplexSessionRouter Interface Defines the interface required to process messages from duplex session channels.

IDuplexSessionRouter Interface
(http://msdn.microsoft.com/en-us/library/system.servicemodel.routing.iduplexsessionrouter(v=vs.110).aspx)