You are employed as the Exchange administrator at Company.com.You are in the process of  installing a new Exchange Server 2010 Organization.After the installation you send a text message to an external client and receive the subsequent non-delivery report （NDR）： "Delivery has failed to these recipients or groups： User1@Company.com （user1@Company.com）.The recipient’s e-mail system isn’t accepting messages now.Please try resending this message later or contact the recipient directly." You attempt to e-mail the user from an external e-mail system with great success.To ensure productivity you need to make sure e-mails can be sent to external clients from within the organization. What should you do？（）

• A、Your best option would be to create an MX record.
• B、Your best option would be to create a Send connector.
• C、Your best option would be to create an SMTP site link.
• D、Your best option would be to create an accepted domain.