Which of the following is called 'Anonymous proxy'?

This proxy server identifies itself as a proxy server but does not make the original IP address available.

This proxy server identifies itself as a proxy server, but makes an incorrect original IP address available through the HTTP headers.

This proxy server identifies itself as a proxy server and also makes the original IP address available through the HTTP headers.

This type of proxy server does not identify itself as a proxy server and does not make available the original IP address.

None of the above