You decide to enable Flashback Database in your Oracle 10g database so that future recoveries will take less time than traditional recoveries. Which of the following parameters must be included in your initialization parameter file before enabling Flashback Database？（）
- A DB_RECOVERY_FILE_DEST only
- B DB_FLASHBACK_RETENTION_TARGET only
- C DB_RECOVERY_FILE_DEST_SIZE and DB_RECOVERY_FILE_DEST only
- D DB_RECOVERY_FILE_DEST and DB_FLASHBACK_RETENTION_TARGET only
- E DB_RECOVERY_FILE_DEST_SIZE， DB_RECOVERY_FILE_DEST and
- F DB_FLASHBACK_RETENTION_TARGET