A System p administrator is reviewing root’s command history on a development server and finds that a junior adminstrator had been attempting to correct a full file system. One of the following commands caused damage that must be corrected. 
Which command was it（）

A.rm /var/preserve/*
B.cat /dev/null > /var/adm/cron/log
C.> /var/adm/wtmp
D.rm /var/adm/ras/errlog