A Windows Communication Foundation (WCF) solution exposes the following service over a TCP binding.(Line numbers are included for reference only.) 01 [ServiceContract] 02 [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple)] 03 public class DataAccessService 04 { 05 [OperationContract] 06 public void PutMessage(string message) 07 { 08 MessageDatabase.PutMessage(message); 09 } 10 [OperationContract] 11 pubic string[] SearchMessages(string search) 12 { 13 return MessageDatabase.SearchMessages(search); 14 } 15 } MessageDatabase supports a limited number of concurrent executions of its methods. You need to change the service to allow up to the maximum number of executions of the methods of MessageDatabase. This should be implemented without preventing customers from connecting to the service. What should you do?（）

• A、Change the service behavior as follows. [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)]
• B、Change the service behavior as follows. [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Single, InstanceContextMode = InstanceContextMode.PerSession)]
• C、Add a throttling behavior to the service, and configure the maxConcurrentCalls.
• D、Add a throttling behavior to the service, and configure the maxConcurrentSessions.