You have an Exchange Server 2010 server that has the Mailbox， Hub Transport， and Client Access server roles installed. You need to ensure that users can send and receive e-mail by using Windows Live Mail or Microsoft Outlook Express.  What should you do on the server（）？ 

• A、Install and then configure the SMTP server feature.
• B、Start the Microsoft Exchange POP3 service and then set the startup type to Automatic.
• C、Modify the properties of the MSExchangePOP3 （TCP-in） Windows Firewall rule.
• D、Modify the properties of the MSExchangeMailSubmission - RPC （TCP-in） Windows Firewall rule.