You recently upgraded from SharePoint Server 2010 to SharePoint Server 2013.
You have not upgraded any site collections.

You have a site collection that contains an InfoPath form library. The InfoPath form library has a
content type named CT1.
You need to verify whether CT1 will conflict with any of the content types in SharePoint Server 2013.
What should you do?

A.
From Site Settings, navigate to Site collection upgrade.

B.
Run the Test-SPContentDatabasecmdlet.

C.
From Site Settings, navigate to Site collection health checks.

D.
From Site Settings, navigate to Content type publishing.

Explanation:
Conflicting content types were found during site collection health check
When you run a site collection health check before upgrading to SharePoint 2013, SharePoint will
check to see if there are any conflicts between existing content types and content types that are
created when you upgrade the site to SharePoint 2013. A conflict occurs when both content types
have the same name.
To fix this issue, you need to rename the existing content type before upgrading.