A user is trying to use Remote Desktop to connect to another computer on the LAN. Theconnection fails. The technician opens up a command prompt and types the following: “telnetcomputernamE. 3389” and also gets the same error message. Which of the following is the MOSTlikely cause of this error, assuming that the OS firewall has been disabled?（）

• A、The antivirus software is blocking the incoming connection.
• B、The ISP is blocking Remote Desktop at their end.
• C、The RDP connection has been configured to use a non-standard port.
• D、The telnet service has not been installed.