Your company has an Exchange Server 2010 Hub Transport server named Hub1.Hub1 receives all e-mail sent to the company from the Internet.You install the anti-spam agents on Hub1.You need to ensure that Hub1 only accepts messages sent to e-mail addresses listed in ActiveDirectory.What should you do？（）

• A、Modify the properties of the Sender Filtering agent.
• B、Modify the properties of the Recipient Filtering agent.
• C、Modify the properties of the default Accepted Domain.
• D、Modify the properties of the default Receive Connector.