A self-hosted Windows Communication Foundation (WCF) service uses a secure HTTP binding with a custom principal permission mode. The binding requires users to provide their Windows logon credentials. You need to retrieve the identity of the caller.What are two possible properties you can use to achieve this goal? (Each correct answer presents a complete solution Choose two)（）

• A、Thread.CurrentPrincipal.Identity.Name
• B、HttpContext.Current.User.Identity.Name
• C、ServiceSecurityContext.Current.PrimaryIdentity.Name
• D、OperationContext.Current.ServiceSecurityContext.PrimaryIdentity.Name