You need to use the least amount of development effort to enable users to log on

You are developing an ASP.NET MVC application to be used on the Internet. The
environment uses Active Directory with delegation to access secure resources.
Users must be able to log on to the application to maintain their personal preferences.
You need to use the least amount of development effort to enable users to log on.
What should you do?

A.
Enable Windows authentication.

B.
Generate server SSL certificates and install them in IIS.

C.
Enable Digest authentication.

D.
Enable Forms authentication.