* A static service must be registered with the local listener to enable DGMGRL to restart instances during the course of broker operations (A): For DGMGRL (Data Guard Manager Command-Line Interface) to perform instance management operations, such as restarting instances, a static service registration in the listener is required. This allows the broker to connect to the database instance even when the instance is not fully up and the dynamic service registration is not available.
* Installing the oracle-database-preinstall-19c package is NOT sufficient to set up operating system kernel parameters for Oracle Net (C): While the oracle-database-preinstall-19c package automates the setting of several kernel parameters to meet the preinstallation requirements for Oracle Database, it does not specifically tailor all settings for Oracle Net in a Data Guard configuration. Additional manual configuration may be required to optimize Oracle Net services for Data Guard operations.
References:
* Oracle Data Guard Broker documentation
* Oracle Net Services Administrator's Guide

According to the requirements stated:
Zero data loss must be guaranteed despite the loss of any one component: This necessitates synchronous redo transport to at least one standby database (for no data loss).
The primary database must be protected against a regional disaster: This implies that there must be a standby database in a different region.
Performance overhead on the primary should be minimized: This suggests that asynchronous transport should be used where possible to reduce the performance impact on the primary.
Downtime on the primary for any reason must be kept to a minimum: This is indicative of a requirement for a fast failover mechanism, possibly with a fast-start failover (FSFO) and high availability.
Given these requirements, the appropriate option that fulfills all these is:
Option C, where 'prima' is the primary database, 'fs1' is the Far Sync instance in the primary region, and 'physt' and 'physt2' are physical standby databases in the primary and remote regions, respectively. In this configuration:
'prima' is set to send redo to 'fs1' using SYNC to guarantee zero data loss.
'fs1' is set to send redo to 'physt' (local standby) using FASTSYNC, which is a low-latency synchronous transport that is optimized for performance.
The Data Guard configuration's protection mode is set to MAXAVAILABILITY to provide the highest level of data protection that is possible without compromising the availability of the primary database.
This configuration ensures that there is zero data loss even if the primary region is completely lost, maintains performance by limiting the synchronous transport to the local region with a Far Sync instance, and has a remote standby database in a separate region for disaster recovery purposes.
Reference:
Oracle Data Guard Concepts and Administration
Oracle Data Guard Broker documentation

Block change tracking is a feature that enhances the efficiency of incremental backups by recording changed blocks in a tracking file. When used with Oracle Active Data Guard:
* It starts the RVWR process on the physical standby database instance (A): When block change tracking is enabled on a physical standby database, the Recovery Writer (RVWR) process is initiated.
This process is responsible for recording the changes to blocks in the block change tracking file, which is then used to optimize incremental backups.
* It allows fast incremental backups to be offloaded to the physical standby database (E): With block change tracking enabled on the physical standby database, fast incremental backups can be offloaded from the primary database. This reduces the workload on the primary database and utilizes the standby database for backup operations, improving overall system performance and efficiency.References:
* Oracle Database Backup and Recovery User's Guide
* Oracle Active Data Guard documentation

A snapshot standby database is a fully updateable standby database that is created by converting a physical standby database into a snapshot standby database. The main characteristics of a snapshot standby database include:
* B: Tablespaces can indeed be dropped in a snapshot standby database because it is updateable and allows all types of DML and DDL operations that do not conflict with the standby role.
* C: Tablespaces can be created in a snapshot standby database for the same reasons that they can be
* dropped; it supports all operations that do not interfere with its standby nature.
* E: Tables can be dropped in a snapshot standby database, as it is a fully updateable standby.
Options A and D are incorrect because 'FAILOVER TO' and 'SWITCHOVER TO' commands are not used with snapshot standby databases in these contexts. A failover converts a standby database into the primary role after the original primary has become unavailable, and is not a reversible role transition. Switchover is a planned role reversal between the primary database and one of its standby databases and is not applicable to snapshot standby databases in the context provided.
Option F is incorrect because a logical standby database cannot be converted into a snapshot standby database directly. A logical standby is used for different purposes such as reporting and querying with real-time data, and its structure is different from a physical standby which can be converted into a snapshot standby.
References: Oracle Data Guard Concepts and Administration guide details the operations allowed on snapshot standby databases and the processes for transitioning between physical, snapshot, and logical standby databases.