You are designing a Windows Phone 7 application. The application must be able to receive data from a Microsoft Windows Communication Foundation (WCF) web service. You need to ensure that authentication requests are passed to the WCF web service. What should you recommend?

A.
OpenID protocol

B.
Windows Identity Framework (WIF)

C.
Window Live ID Single Sign-On (SSO)

D.
basic authentication with credentials in the header