Up to now, your users have been allowed to use cron for their own use. Because some users
have abused the system, you want to block the use of cron by all users, except root. The following
files exist on your system: 
What should you do to block all users, except root, from creating and running cron jobs?
A.
Remove the crontabs associated with each user in the /var/spool/cron/crontabs directory.
B.
Write protect the crontabs associated with each user in the /var/spool/cron/crontabs directory.
C.
Remove the crontabs associated with each offending user in the /var/spool/cron/crontabs
directory.
Explanation: