You have an existing Windows Communication Foundation (WCF) service. You need to ensure that other services are notified when the service is started.
What should you do?

A.
Add the following standard endpoint to the service.
<endpoint name=”udpAnnouncementEndpoint” kind=”udpDiscoveryEndpoint” />

B.
Add the following standard endpoint to the service.
<endpoint name=”udpDiscoveryEndpoint” kind=”udpAnnouncementEndpoint” />

C.
Add a service behavior with the following element.
<serviceDiscovery>
<announcementEndpoints>
<endpoint kind=”udpDiscoveryEndpoint” />
</announcementEndpoints>
</serviceDiscovery>

D.
Add a service behavior with the following element.
<serviceDiscovery>
<announcementEndpoints>
<endpoint kind=”udpAnnouncementEndpoint” />
</announcementEndpoints>
</serviceDiscovery>

Explanation:
A standard endpoint that is used by services to send announcement messages over a UDP binding.
This endpoint inherits from AnnouncementEndpoint and similarly has a fixed contract and supports two discovery versions.
In addition it has a fixed UDP binding and a default address value as specified in the WS-Discovery specifications (WS-Discovery April 2005 or WS-Discovery version 1.1).

Therefore, in the simplest case you do not have to specify any of these values when you create an AnnouncementEndpoint and add it to a service.
eg:
<serviceDiscovery>
<announcementEndpoints>
<endpoint kind=”udpAnnouncementEndpoint”/>
</announcementEndpoints>
</serviceDiscovery>

Configuring Discovery in Confiruration File
(http://msdn.microsoft.com/en-us/library/dd456792.aspx)