You performed the RMAN database backup with the KEEP option. Which two statements are true regarding this backup？（）
- A The backup contains data files， the server parameter file，and the control file even if the control file autobackup is disabled.
- B The KEEP option overrides the configured retention policy.
- C The backup contains only data files and archived redo log files.
- D The KEEP option is an attribute of an individual backup piece.