A corporate network includes a single Active Directory Domain Services (AD DS) domain. The AD DS
infrastructure is shown in the following graphic.

When the Montreal site domain controller is offline, authentication requests for Montreal branch office users are
sent to the Toronto site domain controller.
You need to ensure that when the Montreal Site domain controller is offline, authentication requests for
Montreal branch office users are sent to the Quebec City site domain controller.
What should you do?

A.
Create a site link bndge between the Montreal site and the Quebec City site.

B.
Enable the global catalog role on the Montreal site domain controller.

C.
Modify the Default Domain Policy Group Policy Object.

D.
Delete the Toronto-Montreal Site Link

Explanation:
Reference 1:
http://technet.microsoft.com/en-us/library/cc772592.aspx
Enable Clients to Locate a Domain Controller in theNext Closest Site
You can modify the Default Domain Policy to enable Windows Vista and Windows Server 2008 clients in the
domain to locate domain controllers in the next closest site if no domain controller in their own siteor the
closest site is available.
To enable clients to locate a domain controller in the next closest site
1. Click Start, click Administrative Tools, and thenclick Group Policy Management.
2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then
click Continue.
3. Double-click Forest:forest_name, double-click Domains, and then double-click domain_name.
4. Right-click Default Domain Policy, and then click Edit.
5. In Group Policy Management Editor, in the consoletree, go to Computer Configuration/Policies/
Administrative Templates/System/Netlogon/DC LocatorDNS Records.
6. In the details pane, double-click Try Next Closest Site, click Enabled, and then click OK.
Reference 2:
http://technet.microsoft.com/en-us/library/cc733142.aspx
Enabling Clients to Locate the Next Closest Domain Controller
If you have a domain controller that runs Windows Server 2008 or Windows Server 2008 R2, you can make it
possible for client computers that run Windows Vista, Windows 7, Windows Server 2008, or Windows Server
2008 R2 to locate domain controllers more efficiently by enabling the Try Next Closest SiteGroup Policy
setting. This setting improves the Domain Controller Locator (DC Locator) by helping to streamline network
traffic, especially in large enterprises that have many branch offices and sites.
By default, the Try Next Closest Site setting is not enabled. When the setting is not enabled, DC Locator uses
the following algorithm to locate a domain controller:
Try to find a domain controller in the same site.
If no domain controller is available in the same site, try to find any domain controller in the domain.
If you enable the Try Next Closest Site setting, DCLocator uses the following algorithm to locate a domain
controller:
Try to find a domain controller in the same site.
If no domain controller is available in the same site, try to find a domain controller in the next closest site. A
site is closer if it has a lower site-link cost than another site with a higher site-link cost.
If no domain controller is available in the next closest site, try to find any domain controller in the domain.