You are developing a Windows Communication Foundation (WCF) service to provide an in-memory cache for many Web applications.The service contract is defined as follows. (Line numbers are included for reference only.) 01 [ServiceContract] 02 public interface IDataCache 03 { 04 ... 05 }06 07 08 public class DataCache : IDataCache 09 { 10 ... 11 } You need to ensure that all users share the cache. Which code segment should you insert at line 07?（）

• A、[ServiceBehavior(TransactionIsolationLevel = IsolationLevel.RepeatableRead)]
• B、[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
• C、[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)]
• D、[ServiceBehavior(TransactionIsolationLevel = IsolationLevel.ReadComitted)]