单项选择题 You are creating a Windows Communication Foundation (WCF) service. The service endpoints change frequently. On the service, you add a new ServiceDiscoveryBehavior to the Behaviors collection of the ServiceHost Description property. You need to ensure that client applications can communicate with the service and discover changes to the service endpoints. What should you do?（）

单项选择题 You develop a Windows Communication Foundation (WCF) service that interacts with Microsoft Message Queuing (MSMQ). The service requires sessions. You need to create a custom binding that enables messages sent to the queue to be viewed when you are using a listener tool. Which binding elements should you use?（）

多项选择题 You develop a Windows Communication Foundation (WCF) service that employees use to access bonus information.You define the following service contract. (Line numbers are included for reference only.) 01 [ServiceContract(SessionMode = SessionMode.Required)] 02 public interface IFinancialService 03 { 04 [OperationContract] 05 string Login(int employeeID, string passwordHash); 06 07 [OperationContract] 08 double GetBonus(int month); 09 10 [OperationContract(IsTerminating = true)] 11 void Logout(); 12 } Client application can invoke methods without logging in. You need to ensure that the client applications invoke Login before invoking any other method. You also need to ensure that client applications cannot consume the service after invoking Logout. Which two action should you perform? （）(Each correct answer presents part of the solution. Choose two.)。