You have an Exchange Server 2010 organization named contoso.com.

You have a Client Access server named cas1.contoso.com that is accessible on the Internet.

You access cas1.contoso.com on the Internet by using the following domain names:

* mail.contoso.com
* autodiscover.contoso.com

You need to ensure that mobile devices can use Autodiscover on the Internet.

What should you do?

A.
Set the external URL for Microsoft-Server-ActiveSync to $NULL.

B.
Set the external URL for Microsoft-Server-ActiveSync to https://cas1.contoso.com/Microsoft�Server�ActiveSync.

C.
Set the external URL for Microsoft-Server-ActiveSync to https://mail.contoso.com /Microsoft-Server-ActiveSync.

D.
Set the external URL for Microsoft-Server-ActiveSync to http://autodiscover.contoso.com/Microsoft-Server-ActiveSync.