You are developing a Windows Communication Foundation (WCF) service. The service needs to access out-of-process resources.You need to ensure that the service accesses these resources on behalf of the originating caller. What should you do?（）
- A Set the value of ServiceSecurityContext.Current.WindowsIdentity.ImpersonationLevel to TokenlmpersonationLevel.Impersonation
- B Set the value of ServiceSecurityContext.Current.Windowsldentity.ImpersonationLevel to TokenlmpersonationLevel.Delegation
- C Set the PrincipalPermissionAttribute on the service contract and update the binding attribute in the endpoint element of the configuration file to wsHttpBinding
- D Set the PnncipalPermissionAttribute on the service contract and update the bindingConfiguration attribute in the endpoint element of the configuration file to wsHttpBinding