You have a Microsoft Office SharePoint Server 2007 site.

You upgrade the site to SharePoint Server 2010.

You need to create a Feature that prevents site collection administrators from upgrading the user interface of the site to SharePoint Server 2010.

Which property should you use?

A.
AdministrationSiteType

B.
AllowDesigner

C.
AllowMasterPageEditing

D.
UIVersionConfigurationEnabled

Explanation:
MNEMONIC RULE: “upgrading = UIVersionConfigurationEnabled”

Gets or sets a value that indicates whether to enable the user interface (UI) for changing the version of the UI.

SPWeb.UIVersionConfigurationEnabled Property
http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spweb.uiversionconfigurationenabled.aspx