单项选择题 You are integrating a Windows Communication Foundation (WCF) service within an enterprise-wide Service Oriented Architecture (SOA).Your service has the following service contract: [ServiceContract]public class CreditCardConfirmationService { [OperationContract] boolean ConfirmCreditCard(string ccNumber); double OrderAmount(int orderNumber);} You need to allow the code in the ConfirmCreditCard method to participate automatically in existing transactions.If there is no existing transaction, a new transaction must be created automatically. What should you do?（）

单项选择题 You are creating a Window Commnunication Foundation (WCF) service application. The application needs to service many clients and requests simultaneously. The application also needs to ensure subsequent individual client requests provide a stateful conversation. You need to configure the service to support these requirements. Which attribute should you add to the class that is implementing the service?（）

单项选择题 A Windows Communication Foundation (WCF) service has the following contract: [ServiceContract]public class ContosoService{ [OperationContract] [TransactionFlow(TransactionFlowOption.Mandatory)] [OperationBehavior(TransactionScopeRequired=true, TransactionAutoComplete=false)] void TxOp1(string value) {... }; [OperationContract(IsTerminating=true)] [TransactionFlow(TransactionFlowOption.Mandatory)] [OperationBehavior(TransactionScopeRequired=true, TransactionAutoComplete=false)] void TxOp2(string value) { ... OperationContext.Current.SetTransactionComplete(); }} The service and the clients that call the service use NetTcpBinding with transaction flow enabled. You need to configure the service so that when TxOp1 and TxOp2 are invoked under the same client session, they run under the same transaction context. What should you do?（）