As used in this subdivision:
I. "Accessory dwelling unit" means a residential living unit that is located on a lot containing a single-family dwelling that provides independent living facilities for one or more persons, including provisions for sleeping, eating, cooking, and sanitation, on the same parcel of land as the principal dwelling unit it accompanies. Accessory dwelling units may be constructed at the same time as the principal dwelling unit.
II. "Attached unit" means a unit that is within or physically connected to the principal dwelling unit, or completely contained within a preexisting detached structure.
III. "Detached unit" means a unit that is neither within nor physically connected to the principal dwelling unit, nor completely contained within a preexisting detached structure.