A SharePoint 2010 environment contains a Microsoft SQL Server 2008 R2 database instance named SP-SQL that hosts the databases for the farm. You are upgrading the farm to SharePoint 2013. You need to…

Executing a T-SQL ALTER DATABASE ... SET READ_ONLY statement against each content database and service application database forces SQL Server to reject write operations, allowing the existing SharePoint 2010 farm to continue serving read requests to users uninterrupted while the databases are detached, copied, and attached to the SharePoint 2013 farm. This is the prescribed database-attach upgrade approach that prevents data changes mid-migration and ensures farm contents remain unmodified and accessible throughout the process.

Running a command-line tool per site collection operates at the SharePoint application layer and does not place the underlying SQL databases into read-only mode, so the farm content cannot be guaranteed to remain unmodified during the upgrade.

Windows PowerShell cmdlets targeting each web application in SharePoint 2010 manage SharePoint-level configuration but do not set the SQL Server databases to READ_ONLY, which is the SQL-level mechanism required to preserve content integrity and continued user access during a database-attach upgrade.

As presented, this option is textually identical to option A and appears to be a duplicate or data error in the question; the correct action is the T-SQL READ_ONLY approach described in option A.