Your company has an Active Directory Domain Services (AD DS) domain. You are installing the RD Session Host (RD Session Host) role service in Server Manager on a server that runs Windows Server 2008 R2. The Audio and video playback check box on the Configure Client Experience page is not available. You need to ensure that you can enable audio and video playback for users connecting to the RD Session Host server. Which two actions should you perform? （）

• A、Start the Windows Audio service.
• B、Install the Desktop Experience feature.
• C、Install Connection Manager Administration Kit feature.
• D、Start the Windows  Audio EndPoint Builder service.