A. to configure RMAN to maintain backup information in the RMAN repository for seven days
B. to configure RMAN to maintain backup information in the control file for at least seven days
C. to display the list of files that have not been backed up for the last seven days
D. to display the list of files that must be backed up within seven days

A. The block change tracking feature is enabled， and the information about the system change number is written in the change tracking file.
B. The block change tracking feature is enabled， and the information about the log sequence number is written in the change tracking file.
C. The block change tracking feature is enabled， and the information about the blocks that are changed since the last backup is written in the change tracking file.
D. The block change tracking feature is enabled， and the information about the locations of the datafiles and the online redo log files are written in the change tracking file.