Your network consists of one Active Directory domain. You have a single site. You deploy a new
Active Directory-integrated application on a server that runs Windows Server 2008. The application
sends a large number of LDAP queries to the domain controllers. You plan to install a new domain
controller to respond to the LDAP queries. You need to reduce the number of authentication
requests client computers send to the new domain controller. What should you do?

A.
Create a new site and disable the Bridge all site links option.

B.
Create a new site. Move the application server and the new domain controller to the new site.

C.
Create a new organizational unit (OU). Move the application server and the new domain
controller to the new OU.

D.
Create two new sites. Move the application server to one site and the new domain controller to
another site. Create a new site link that connects the two sites.

Explanation:
When the client receives the SRV records, it performs a quick LDAP ping to all of them by sending
out a bind query to UDP port 389. The first domain controller to respond is selected as the primary
LDAP server by the client. You cannot configure a preferred domain controller for a client. If you
have a large LAN and you want to compartmentalize your clients based on their area of a campus
LAN or MAN (metropolitan area network), you must structure your replication topology around
multiple sites. Therefore to reduce the number of authentication requests that the client computers
would send to the new domain controller, you need to create a new site in the domain and then
move the server on which application is installed and the new domain controller to the new site
Understanding Active Directory Services
http://www.windowsitlibrary.com/Content/716/06/5.html