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
微信支付 
支付宝支付