Please enter the command with all parameters and arguments, that could be used by root to list the cron jobs for the user john.

Please enter the command with all parameters and arguments, that could be used by root to list the
cron jobs for the user john.

Answer: crontab -u

Explanation:
john -l

From the crontab manpage
-u Specify the name of the user
-l Display the current crontab on standard output