You are using Oracle Database 10g. The LOG_ARCHIVE_FORMAT parameter is set to  ’LOG%t_%s_%r.dbf’.  Why is %r used in the file name format？（） 

• A、to uniquely identify the archived log files with the restore operation
• B、to uniquely identify the archived log files with the redo log group number
• C、to uniquely identify the archived log files for each incarnation of the database
• D、to uniquely identify the archived log files with the number of recovery operations performed