Which three statements are true about using flashback database in a multitenant container database (CDB)?

In a multitenant CDB, the root container can be flashed back independently of PDBs; after flashing back the CDB, individual PDBs that should not be reverted can be recovered forward using RMAN, allowing selective point-in-time management per container.

Flashback database is enabled by issuing ALTER DATABASE FLASHBACK ON while the CDB is in the MOUNT state; the database cannot be open when this command is executed, making the mounted state a prerequisite.

In the shared undo mode available through Oracle 12.1, individual PDB flashback is not supported independently - a flashback operation affects the entire CDB including all PDBs, making this statement false in that context.

DB_FLASHBACK_RETENTION_TARGET specifies the desired retention period in minutes for flashback logs in the fast recovery area; setting this parameter is required so Oracle retains sufficient flashback log data to support the desired recovery window.

This choice is truncated but implies that restore points cannot be used as a flashback target, which is incorrect - Oracle supports flashing back a CDB to a named restore point, an SCN, or a specific point in time.