You are designing a Windows Azure application.   The application will use a Windows Azure AppFabric Service Bus message buffer.  You need to recommend an approach for ensuring that only authorized users can discover and use the message buffer.  What should you recommend？（）

• A、 Make the message buffer discoverable to listeners and require authorization.
• B、 Make the message buffer discoverable to managers and do not require authorization.
• C、 Make the message buffer publicly discoverable.  Include a Simple Web Token （SWT） in each message.
• D、 Make the message buffer discoverable to managers.  Include a Simple Web Token （SWT） in each message.