Then which of the following you can use in your design?

In designing the security for your enterprise application with multiple Web services, you don’t want that each of the services handle user authentication by itself. Then which of the following you can use in your design?

A.
enable secure conversation for each service

B.
a centralized Policy Decision Point (PDP) via XACML

C.
a Security Token Service (STS)

D.
use transport level security with SSL