Which authentication model should you design for the SharePoint farm?

You are designing a SharePoint 2010 implementation that will be used by a company with a variety of
authentication systems. The authentication system must provide:
Authentication for Windows-based and Linux-based systems
.Support for multiple authentication types
.Strong real-time authentication for applications
.Delegation of user identity among applications
You need to use standard SharePoint 2010 technologies to meet all these requirements.
Which authentication model should you design for the SharePoint farm?

A.
Claims based

B.
Forms based

C.
Kerberos

D.
Windows