You are developing an application that will use custom authentication and role-based security. You need to write a code segment to make the runtime assign an unauthenticated principal object to each running thread. Which code segment should you use?

A.
Dim objDomain As AppDomain = AppDomain.CurrentDomainobjDomain.SetPrincipalPolicy( _ PrincipalPolicy.WindowsPrincipal)

B.
Dim objDomain As AppDomain = AppDomain.CurrentDomainobjDomain.SetThreadPrincipal(New WindowsPrincipal(Nothing))

C.
Dim objDomain As AppDomain = AppDomain.CurrentDomainobjDomain.SetAppDomainPolicy( _ PolicyLevel.CreateAppDomainLevel())

D.
Dim objDomain As AppDomain = AppDomain.CurrentDomainobjDomain.SetPrincipalPolicy( _ PrincipalPolicy.UnauthenticatedPrincipal)