单项选择题

A. After two days, a backup will be marked obsolete
B. After two days, a backup will be deleted from the media
C. If the RMAN repository has records of two or more recent backups of a file, then older backups will be deleted from the media.
D. If the RMAN repository has records of two or more recent backups of a file, then older backups will be marked obsolete.