You need to ensure that users in fabrikam.com can find their mailboxes automatically

A company named Contoso, Ltd., has an Exchange Server 2013 organization. The primary
SMTP suffix for all users is contoso.com.
A company named Fabrikam, Inc., has an Exchange Server 2010 organization. The primary
SMTP suffix for all users is fabrikam.com.
The users in both organizations access their email by using Microsoft Outlook 2010 and
Outlook Anywhere. All of the users work from domain-joined client computers that connect to
the internal network.
Contoso acquires Fabrikam.
You establish a cross-forest trust between the Contoso forest and the Fabrikam forest.
In fabrikam.com, you create a user named User1. In contoso.com, you create a linked
mailbox for User1 and you set the primary SMTP address to [email protected].
User1 reports that Outlook 2010 fails to configure his mail profile automatically. User1 can
manually configure his profile and connect to his mailbox.
You need to ensure that users in fabrikam.com can find their mailboxes automatically.
What should you do in contoso.com?

A.
Create a DNS record named autodiscover.fabrikam.com. Point the record to the virtual IP
address of the Client Access servers.

B.
Modify the ExternalURL of the Autodiscover virtual directory on the Exchange Servers
2013 servers.

C.
Modify the Autodiscover Service Connection Point (SCP).

D.
Run the Export-AutoDiscoverConfig cmdlet on an Exchange Server 2013 server.