You need to configure SQL Server to support the migration

A SharePoint environment contains an instance of Microsoft SQL Server 2008 R2.
You plan to migrate data from the existing database to a new instance of SQL Server 2012.
You need to configure SQL Server to support the migration. You must accomplish this goal without
requiring any SharePoint application configuration changes.
What should you do?

A.
On the SQL Server, configure a named instance.

B.
On all servers in the farm, configure a SQL Server alias.

C.
On all servers in the farm, configure SQL Server database mirroring.

D.
Create a single-node SQL Server cluster.