单项选择题 You are developing a new version of an existing message contract named CustomerDetailsVersion1. The new version of the message contract must add a Department field of type String to the SOAP header.You create a new class named CustomerDetailsVersion2 that inherits from CustomerDetailsVersion1. You need to ensure that all client applications can consume the service. Which code segment should you use?（）

单项选择题 You are developing a Windows Communication Foundation (WCF) client application. The client application contains the following code. [ServiceContract] public interface ISocialStatus { [OperationContract] [WebInvoke(UriTemplate = "/statuses/update.xml?status-{text}")] void UpdateStatus(string text); } public class SocialClient : ClientBase, ISocialStatus { ... } The configuration file contains the following lines. binding="webHttpBinding" contract="SocialApp.ISocialStatus" bindingConfiguration="BindingConfig" /> You need to ensure that the service is consumed. Which code segment should you use?（）

单项选择题 You are configuring services to be discoverable. The services must be discoverable without relying on a central server. Client applications that consume the services are on a network segment that is separate from the network segment that the services are located on.A firewall blocks all TCP ports between the two network segments, but allows other protocols to pass through.You need to ensure that the client applications can discover the services. What should you do?（）