Which THREE statements about crontab are true?

A.
Every user may have their own crontab.

B.
Changing a crontab requires a reload/restart of the cron deamon.

C.
The cron daemon reloads crontab files automatically when necessary.

D.
hourly is the same as “0 * * * *”.

E.
A cron daemon must run for each existing crontab.

Explanation:
From the man pages:
Additionally, cron checks each minute to see if its  spool  directory’s modtime  (or  the  modtime on /etc/crontab) has changed, and if it has, cron will then examine the modtime on all  crontabs  and  reload  those which have changed.  Thus cron need not be restarted whenever a crontab file is modified.  Note that the crontab(1) command updates the modtime of the spool directory whenever it changes a crontab.