Which scenario requires a survey and plat recording under the Illinois Plat Act?

The requirement for a survey and plat recording under the Illinois Plat Act is triggered when land is subdivided into multiple plots or lots. In the context of this question, the correct answer highlights an essential aspect of property division.

The scenario involving the division of a 20-acre parcel into five equal lots necessitates a detailed survey and plat. This is because the act of subdividing a parcel into multiple lots typically requires compliance with local regulations, which are in place to ensure proper oversight of development and land-use practices.

When landowners create new lots, especially in substantial subdivisions like this one, it's crucial for a survey to be conducted to establish clear boundaries and ensure that all lots adhere to zoning laws and standards. This entails creating a plat that accurately represents the new division of land, which is an official map that delineates the subdivision and provides necessary information about the dimensions and layout of the lots.

Other scenarios presented in the question do not meet the threshold requiring a full survey and plat recording as they involve either single lot conveyances or fewer lots that may sometimes be addressed under different regulations or exemptions. Thus, the division of a 20-acre parcel into five equal lots specifically calls for compliance with the Plat Act, making that scenario distinctly relevant.