You need to ensure that all users can access SaasApp1

Your company network includes users in multiple directories.
You plan to publish a software-as-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:
* When you get deeper into using Windows Azure Active Directory, you’ll run into new terminology. For
instance, is called “directory” is also referred to as a Windows Azure AD Tenant or simply as “tenant.” This
stems from the fact that WAAD () Windows Azure Active Directory is a shared service for many clients. In this
service, every client gets its own separate space for which the client is the tenant. In the case of WAAD this
space is a directory. This might be a little confusing, because you can create multiple directories, in WAAD
terminology multiple tenants, even though you are a single client.
* Multitenant Applications in Azure
A multitenant application is a shared resource that allows separate users, or “tenants,” to view the application
as though it was their own. A typical scenario that lends itself to a multitenant application is one in which all
users of the application may wish to customize the user experience but otherwise have the same basic
business requirements. Examples of large multitenant applications are Office 365, Outlook.com, and
visualstudio.com.

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