Is it necessary to start the SQL Server database and enable TCP/IP before starting the Historian?

The correct response indicates that both the SQL Server database must be running and the TCP/IP protocol must be enabled before starting the Historian. This is essential because the Historian relies on the SQL Server for data storage and retrieval functions.

When the SQL Server database is running, it can accept connections from the Historian, allowing it to properly store and access the historical data it collects. Furthermore, enabling TCP/IP is crucial as it allows network communication and data transfer between the Historian and the SQL Server. Without both components functioning, the Historian would not be able to interact with the database, thus impairing its capability to log, retrieve, or manage data effectively.

In summary, starting the SQL Server database ensures it is available for use, while enabling TCP/IP ensures that the communication between both systems is possible, thus making option A the most accurate and necessary condition for the Historian's operation.