You have an Exchange organization. All Servers in the organization have Exchange Server 2010 SP1 installed.

The organization contains five Hub Transport servers. All of the Hub Transport servers are listed as source servers for the Send connector to the Internet.

You need to prevent a Hub Transport Server named Hub1 from sending and receiving email messages from the Internet. The solution must meet the following requirements:

* Ensure that Mailbox servers can deliver email messages to Hub1
* Ensure that all other Hub Transport server can deliver email messages to the Internet.

What should you do first on Hub1?

A.
Suspend all message queues.

B.
Disable all Receive connectors and Send connectors.

C.
Stop the Microsoft Exchange Mail Submission Service.

D.
Stop the Microsoft Exchange Transport Service.

Explanation:
The first thing you do is suspend the queues on Hub1.
Then, you modify the Internet Send connector and remove Hub1 as a source server.
Finally, you modify the default Receive connector for Hub1 to disable Anonymous permissions.

Reference:

http://technet.microsoft.com/en-us/library/bb124034.aspx
http://technet.microsoft.com/en-us/library/bb125022.aspx