You need to ensure that all users can access SaasApp1

Your company network includes users in multiple directories. You plan to publish a softwareas-a-service application named SaasApp1 to Azure Active
Directory.
You need to ensure that all users can access SaasApp1.
What should you do?

A.
Configure the Federation Metadata URL

B.
Register the application as a web application.

C.
Configure the application as a multi-tenant.

D.
Register the application as a native client application.

Explanation:
http://msdn.microsoft.com/en-us/library/azure/dn151789.aspx