A Far Sync instance is a special kind of Oracle Data Guard configuration that allows synchronous redo transport from a primary database to a remote standby database with minimum impact on the primary database's performance. The Far Sync instance receives redo data synchronously from the primary database (A), then ships it asynchronously to the remote standby database, thus extending zero data loss protection over longer distances and higher network latency environments than would be practical with a synchronous standby alone. The Far Sync instance does not apply the redo data; it just receives and ships it (E). A Far Sync instance does not have data files, and it cannot apply redo to stay synchronized with the primary database.
References:Oracle Database High Availability Overview and Oracle Data Guard Concepts and Administration documentation detail the role and configuration of Far Sync instances, including how they contribute to achieving zero data loss disaster recovery over long distances.

In a Data Guard configuration where the protection mode is set to Maximum Availability and synchronous redo transport is enabled, if the standby destination fails to acknowledge the reception of redo within the net_timeout period, the primary database will terminate the synchronous redo transport mode connections to the standby database to protect the primary database from hanging (C). The primary database then operates in a Maximum Performance mode until the issue is resolved. This behavior ensures that the primary database can continue to process transactions even when the standby database is temporarily unavailable.
References:The Oracle Data Guard Broker documentation and Oracle Data Guard Concepts and Administration guide detail the behavior of different protection modes and the response to network timeouts, including the fallback to asynchronous redo transport to maintain primary database availability.

When STANDBY_FILE_MANAGEMENT is set to AUTO, the Oracle Data Guard automatically creates, deletes, and renames files on the standby database to match the changes made on the primary database. The tasks that lead to the automatic creation of files on the standby include:
Adding a data file or creating a tablespace (C): When a new tablespace is created or a new data file is added on the primary database, the standby database automatically replicates this action, maintaining structural consistency with the primary database.
Creating a PDB from the existing PDB within the same CDB (D): Creating a new Pluggable Database (PDB) within a Multitenant Container Database (CDB) on the primary database triggers an automatic creation of the corresponding PDB within the standby CDB.
Reference:
Oracle Data Guard Concepts and Administration Guide

In a Data Guard environment, offloading backups to a physical standby database has certain requirements:
* A: Once the primary database is registered in an RMAN catalog, the standby database can also be
* registered. This allows RMAN to manage backups coherently across both databases and leverage the standby database for backup purposes without interfering with the primary database's workload.
* C: Backups of the standby control file taken while connected to the catalog where the database is registered can be used to restore the control file on the primary database. This ensures that backup metadata is consistent across the Data Guard configuration.
Options B and D are incorrect because there is no strict requirement for the order in which the primary and standby databases must be registered in an RMAN catalog. However, it is a common practice to register the primary database first.
References: The Oracle Database Backup and Recovery User's Guide provides detailed procedures on how to manage RMAN backups in a Data Guard environment, including offloading backups to a standby database.

To meet the requirements of automatic failover and the highest level of protection without data loss, the combination of FASTSYNC redo transport mode and Maximum Availability protection mode is appropriate. FASTSYNC ensures that the performance impact on the primary database is minimized while still providing synchronous transport. Maximum Availability protection mode offers the highest level of data protection without compromising the availability of the primary database. In case of a network failure or a standby failure, the primary will not halt, avoiding disruption to the primary database operations.
Reference
Oracle Data Guard Concepts and Administration guide, which details the different protection modes and their respective levels of data protection and impact on database operations.