Your network contains an Active Directory domain named contoso.com.
All servers run Windows Server 2008 R2.
Routers on the network support multicast transmissions.
A server named Server1 has the Windows Deployment Services (WDS) server role installed.
A custom Windows 7 image is available for download from Server1.
You need to deploy the image to 100 new computers by using multicast.
The solution must prevent computers that use low-bandwidth connections from slowing the deployment to computers that use high-bandwidth connections.

What should you do?

A.
Enable Auto-Cast.

B.
Enable Scheduled-Cast.

C.
From the WDS server properties, adjust the Transfer Settings.

D.
From the WDS server properties, modify the Multicast IP Address settings.

Explanation:
To enable multicasting of an install image
Before you create a transmission, you should set the transfer policy for the server. To do this, right-click the server, click Properties, click the Multicast tab, and select an option under Transfer Settings. These settings allow you to enable the following:

Multiple stream transfer. The first option under Transfer Settings uses a single stream for all multicast clients, regardless of client speed. The next two options allow you to separate slower clients into their own multicast stream, which enables faster clients to complete their deployment more quickly instead of being held back by slower clients. These settings are only available for clients that boot into a boot image from Windows 7 or Windows Server 2008 R2.

Source: http://technet.microsoft.com/en-us/library/cc726063.aspx