Which two statements are true about a duplicate database that is created by using the DUPLICATE command in RMAN?

Which two statements are true about a duplicate database that is created by using the
DUPLICATE command in RMAN? (Choose two.)

A.
It is a copy or a subset of the target database.

B.
It is opened in RESTRICT mode after a duplicating operation.

C.
It is created by using backups and archived redo log files from the target database.

D.
It is created with the same database identifier (DBID) as that of target database.

Explanation:
Duplicating a Database
Overview of RMAN Database Duplication
Database duplication is the use of the DUPLICATE command to copy all or a subset of the
data in a source database. The duplicate database (the copied database) functions entirely
independently from the source database (the database being copied).
Purpose of Database Duplication
If you copy a database with operating system utilities instead of the DUPLICATE command,
then the DBID of the copied database remains the same as the original database. To
register the copy database in the same recovery catalog with the original, you must change
the DBID with the DBNEWID utility (see Oracle Database Utilities). In contrast, the
DUPLICATE command automatically assigns the duplicate database a different DBID so
that it can be registered in the same recovery catalog as the source database.
Backup-Based Duplication
In backup-based duplication, RMAN creates the duplicate database by using pre-existing
RMAN backups and copies. This technique of duplication uses one of the following mutually
exclusive subtechniques: Duplication without a target database connection, RMAN obtains
metadata about backups from a recovery catalog.
Duplication without a target database connection and without a recovery catalog. RMAN
obtains metadata about where backups and copies reside from BACKUP LOCATION.

Duplication with a target database connection. RMAN obtains metadata about backups from
the target database control file or from the recovery catalog.
How RMAN Duplicates a Database
For backup-based duplication, the principal work of the duplication is performed by the
auxiliary channels. These channels correspond to a server session on the auxiliary instance
on the destination host. For active database duplication the primary work is performed by
target channels. RMAN must perform database point-in-time recovery, even when no explicit
point in time is provided for duplication. Point-in-time recovery is required because the online
redo log files in the source database are not backed up and cannot be applied to the
duplicate database. The farthest point of recovery of the duplicate database is the most
recent redo log file archived by the source database.
As part of the duplicating operation, RMAN automates the following steps:
1. Creates a default server parameter file for the auxiliary instance if the following conditions
are true:
Duplication does not involve a standby database.
Server parameter files are not being duplicated.
The auxiliary instance was not started with a server parameter file.
2. Restores from backup or copies from active database the latest control file that satisfies
the UNTIL clause requirements.
3. Mounts the restored or copied backup control file from the active database.
4. Uses the RMAN repository to select the backups for restoring the data files to the auxiliary
instance. This step applies to backup-based duplication.
5. Restores and copies the duplicate data files and recovers them with incremental backups
and archived redo log files to a noncurrent point in time.
6. Shuts down and restarts the database instance in NOMOUNT mode.
7. Creates a new control file, which then creates and stores the new DBID in the data files.
8. Opens the duplicate database with the RESETLOGS option and creates the online redo
log for the new database.