You are an Enterprise administrator for contoso.com. The corporate network of the company consists of a single Active Directory domain. The company has decided to open 2 new branch offices and deploy 1,000 new Windows Vista Enterprise Edition computers.

The Windows Vista installations need to be done using Pre-boot Execution Environment (PXE) network adapters that those 1000 computers already have.

Which of the following options would you choose to ensure that 50 simultaneous installations of Windows Vista can be done in minimum amount of time and the impact of network operations during the deployment of the new computers is minimized?

A.
Install Windows Deployment Services (WDS) server role and configure all the routers with IP Helper tables.

B.
Install Windows Deployment Services (WDS) server role and configure eachWDS server by using legacy mode.

C.
Install both Windows Deployment Services (WDS) server role and Transport Server role services and then configure the Transport Server with a static multicast address range.

D.
Install both Windows Deployment Services (WDS) server role and Transport Server role services and then configure the Transport Server to use a custom network profile.

E.
None of the above

Explanation:
To ensure that 50 simultaneous installations of Windows Vista in minimum amount of time in a Pre-boot Execution Environment, you need to deploy the Windows Deployment Services (WDS) server role and the Transport Server feature. You can install both the Deployment Server and Transport Server role services (which is the default installation) or only Transport Server role services.

The Windows Deployment Services (WDS) enables you to automate the deployment of Windows operating systems. You can use it to set up new computers by using a network-based installation. This means that you do not have to install each operating system directly from a CD or DVD

You can configure Transport Server to enable you to boot from the network using Pre-Boot Execution Environment (PXE) and Trivial File Transfer Protocol (TFTP), a multicast server, or both.

The Transport Server role service provides a subset of the functionality of Windows Deployment Services. It contains only the core networking parts. You can use Transport Server to create multicast namespaces that transmit data (including operating system images) from a stand-alone server. The stand-alone server does not need Active Directory, DHCP, or DNS. You can

If multiple servers are using multicast functionality on a network (Transport Server, Deployment Server, or another solution), it is important that each server is configured so that the multicast IP addresses do not collide. Otherwise, you may encounter excessive traffic when you enable multicasting. Note that each Windows Deployment Services server will have the same default range. To work around this issue, specify static ranges that do not overlap to ensure that each server is using a unique IP address

Reference: Transport Server
http://technet.microsoft.com/en-us/library/cc771645.aspx