A.Retainthedatafilebackupfor7days.
B.Runtherecoverprocessevery7days.
C.Destroythephysicalbackupfilesevery7days.
D.Destroythephysicalbackupfilesolderthan7days.
E.Retainonebackupofeachdatafileforatleast7days.
F.Keepthecataloginformationinthecontrolfilefor7days.
正确答案：参考E
