You are developing a Windows Communication Foundation (WCF) service that does not operate on a duplex channel.You find that operations do not start until all previous operations have finished. The service hosting code contains the following lines.var service = new WarehouseService（　）; var host = new ServiceHost(service);You need to ensure that new operations do not wait for previous operations to finish. Which attribute should you use to decorate the service?（）

• A、[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single, ConcurrencyMode=ConcurrencyMode.Multiple)]
• B、[CallbackBehavior(ConcurrencyMode=ConcurrencyMode.Multiple)]
• C、[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single, ConcurrencyMode=ConcurrencyMode.Single)]
• D、[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single, ConcurrencyMode=ConcurrencyMode.Reentrant)]