Which solution is correct for these requirements?

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Your expertise is requested for these customer requirements:
1. The Data Guard environment must be in maximum protection mode.
2. Reports must be offloaded to a physical standby database.
3. There must be no lag between the primary and standby databases that affect the reports produced.
4. The primary database must be resilient in case of a single network failure.
Which solution is correct for these requirements?

A.
two standby databases, at least one of them a physical standby with Real-Time Query enabled and the
STANDBY_MAX_DELAY parameter set to zero, receiving redo from the primary with asynchronous
transport

B.
two standby databases, at least one of them a physical standby with Real-Time Query enabled and the
STANDBY_MAX_DATA_DELAY parameter set to zero, receiving redo from the primary with synchronous
transport

C.
one physical standby database with Real-Time Query enabled, receiving redo from two Far Sync instances
that are connected the primary

D.
one physical standby database with Real-Time Query enabled and the STANDBY_MAX_DATA_DELAY
parameter set to zero, receiving redo from the primary with synchronous transport

E.
two physical standby databases with Real-Time Query enabled, receiving redo from the primary with the
LOG_ARCHIVE_DEST_n attributes SYNC NOAFFIRM to minimize the performance impact on the primary

Explanation:
If STANDBY_MAX_DATA_DELAY is set to 0, a query issued to a physical standby database is guaranteed to
return the exact same result as if the query were issued on the primary database, unless the standby database
is lagging behind the primary database, in which case an ORA-3172 error is returned.
Real-time Query Restrictions include:
The standby database must receive redo data via the SYNC transport.
Note: In an Active Data Guard environment, this session parameter can be used to specify a session-specific
apply lag tolerance, measured in seconds, for queries issued by non-administrative users to a physical standby
database that is in real-time query mode.
Incorrect Answers:
C, D: Maximum Protection mode ensures that zero data loss occurs if a primary database fails.
Because this data protection mode prioritizes data protection over primary database availability, Oracle
recommends that a minimum of two standby databases be used to protect a primary database that runs in
maximum protection mode to prevent a single standby database failure from causing the primary database to
shut down.
E: Should use STANDBY_MAX_DATA_DELAY parameter set to zero.
https://docs.oracle.com/cd/B28359_01/server.111/b28294/protection.htm
https://chenguangblog.wordpress.com/tag/standby_max_data_delay/

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