Which crontab entry could be used to set the system time at regular intervals?

A.
1 0 * * * date $d $t $24

B.
1 0 * * * ntpdate ntp1.digex.net

C.
1 0 * * * date ntp1.digex.net

D.
1 0 * * * runcron date ntp1.digex.net

E.
1 0 * * * settime $d $t $24