While installing third-party software, a technician wants to monitor logs on the system continuously. Which of the following commands should the technician issue to monitor the logs?

The `cat /var/log/kern.log` command displays the entire content of the `kern.log` file at once and then exits, making it unsuitable for continuous monitoring of new entries.

The `grep -e /var/log/httpd/access.log` command is syntactically incorrect; `grep` expects a pattern as an argument, not just a file, and it does not continuously monitor a file for new entries.

The `head -n /var/log/secure` command displays only the first `n` lines of the `secure` log file and then exits, which is not suitable for continuous monitoring of new entries.

The `tail -f /var/log/messages` command displays the last lines of the `/var/log/messages` file and then continuously outputs new lines as they are appended to the file. The `-f` option (follow) is essential for real-time monitoring of logs during an installation or operation.