Form M1PR instructions - Minnesota Department of Revenue shows property types as follows: homestead, non-homestead, commercial, and special homestead (blind or disabled).
When you go through the Minnesota entry screens in TurboTax, there is a dropdown box for property classification. The first selection is Residential Homestead, and then the box changes to 1a automatically.
A class 1a residential homestead is a property owned by a Minnesota resident and is occupied by that person as their primary residence. See here for more information from the State of Minnesota on this topic.
Please see this thread for another discussion of this topic.