A. cd /var/spool/cron/crontabs，uncomment the lines in the adm file， in order to start gathering statistics.
B. cd /var/spool/cron/crontabs； uncomment the lines in the sys file， in order to start gathering statistics.
C. cd /usr/lib/cron/； vi the adm file； startsrc -s sadc
D. cd /usr/lib/cron/； vi the sys file； startsrc -s sadc