You administer a Microsoft SQL Server 2012 database. The database is currently configured to log ship to a
secondary server.
You are preparing to cut over to the secondary server by stopping log-shipping and bringing the secondary
database online. You want to perform a tail-log backup.
You need to leave the primary database in a restoring state.
Which option of the BACKUP LOG command should you use?

A.
NO_TRUNCATE

B.
NORECOVERY

C.
STANDBY

D.
FORMAT

Explanation:
It is recommended that you take a tail-log backup in the following scenarios:
* If the database is online and you plan to perform a restore operation on the database, begin by backing up the
tail of the log. To avoid an error for an online database, you must use the … WITH NORECOVERY option of
the BACKUP Transact-SQL statement.
Note: A tail-log backup captures any log records that have not yet been backed up (the tail of the log) to prevent
work loss and to keep the log chain intact. Before you can recover a SQL Server database to its latest point in
time, you must back up the tail of its transaction log. The tail-log backup will be the last backup of interest in the
recovery plan for the database.
https://docs.microsoft.com/en-us/sql/relational-databases/backup-restore/tail-log-backups-sqlserver