问题：

[单选]

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?（）

A .
B .
C .
D .