You are creating a Window s Communication 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?

A.
[ ServiceBehavior ( InstanceContextMode = InstanceContextMode.PerCall ,
ConcurrencyMode = ConcurrencyMode.Reentrant )]

B.
ServiceBehavior ( InstanceContextMode = InstanceContextMode.PerSession ,
ConcurrencyMode = ConcurrencyMode.Multiple )]

C.
[ ServiceBehavior ( InstanceContextMode = InstanceContextMode.PerCall ,
ConcurrencyMode = ConcurrencyMode.Multiple )]

D.
[ ServiceBehavior ( InstanceContextMode = InstanceContextMode.PerSession ,
ConcurrencyMode = ConcurrencyMode.Single )]