After a successful switchover operation in a Data Guard environment, the new primary database (the former standby) will be open read-write (option A). If the former primary database transitions to a logical standby database, it will also be open read-write (option C), allowing it to apply redo data while servicing read-only queries. The former primary, if converted to a physical standby, will adopt the state that the former physical standby database was in prior to the switchover, which can vary based on the configuration prior to the switchover (option D). The state of a physical standby database can range from mounted to open read-only, depending on whether Real-Time Query was enabled. Thus, the exact state will depend on the pre-switchover setup. It's also essential to highlight that options B and E suggest specific states for a former primary turned logical standby, and a former primary turned physical standby, respectively, but these states are not fixed and depend on the configurations set up by the database administrators. Reference: The answers are corroborated by Oracle's documentation on Data Guard switchovers, specifically in the Oracle Data Guard Concepts and Administration guide, which explains the roles and states of databases in a Data Guard configuration before and after switchovers.

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.
Reference:
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.

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.

* Synchronous redo transport for zero data loss (B): To guarantee zero data loss in the case of a disaster, synchronous redo transport must be configured between the primary and standby databases.
* Conversion to snapshot standby for testing (B): A physical standby database can be temporarily converted into a snapshot standby database to perform real application testing. After testing is completed, the snapshot standby can be converted back to a physical standby to resume its disaster recovery role.
References:
* Oracle Data Guard Concepts and Administration Guide
* Oracle Database Testing Guide