You create an application by using Microsoft Visual Studio .NET 2008 and the .NET Framework 3.5.
The application design specifies the following components:
– A user interface implemented as an ASP.NET 3.5 Web application
– A Microsoft SQL Server 2005 database to store business data
– A Windows Communication Foundation (WCF) service that authenticates users that have their credentials stored in the SQL Server database
– A business data service to transfer data between the user interface and the SQL Server database
– In future releases, the application must also be able to authenticate business partners who use non-Microsoft directory servers to store user credentials.
You need to ensure that the application design meets the extensibility requirements.
What should you do?

A.
Implement the business data service as a WCF service.

B.
Host the Web application on multiple load-balanced Web servers.

C.
Add an abstraction layer between the user interface and the authentication service.

D.
Implement database objects that store the corporate user credentials in the same SQL Server database as the business data.