Your company has a main officeand four branch offices.
An Active Directory siteexists for each office.
Each sitecontains one domain controller.
Each branch officesitehas a site link to the main office site.
You discover that the domain controllers in the branch offices sometimes replicate directly to each
other.
You need to ensure that the domain controllers in the branch offices only replicate to the domain
controller in the main office.
What should you do?

A.
Modify the firewall settings for the main office site.

B.
Disable the Knowledge Consistency Checker (KCC) for each branch office site.

C.
Disable site link bridging.

D.
Modify the security settings for the main office site.

Explanation:
Reference:
http://technet.microsoft.com/en-us/library/cc757117.aspx
Configuring site link bridges
By default, all site links are bridged, or transitive. This allows any two sites that are not connected by an explicit
site link to communicate directly, through a chain of intermediary site links and sites. One advantageto bridging
all site links is that your network is easier to maintain because you do not need to create a site link to describe
every possible path between pairs of sites.
Generally, you can leave automatic site link bridging enabled. However, you might want to disableautomatic
site link bridging and create site link bridges manually just for specific site links, in the following cases:
(…)
You have a network routing or security policy in place that prevents every domain controller from being able
to directly communicate with every other domain controller.