Final answer:
In the context of the Land Ordinance of 1785, 'sections' were one-square-mile parcels of land, each typically consisting of 640 acres and making up part of townships in the Northwest Territory. Option b) is correct.
Step-by-step explanation:
In the context of the Land Ordinance of 1785, "sections" refer to the subdivisions within the townships that were created during the surveying process of the Northwest Territory. Each township was divided into thirty-six sections, with each section consisting of 640 acres. This method of dividing land aimed at organizing the sale and settlement of the frontier post-Revolutionary War.
Sections of land could be further subdivided into smaller parcels, like quarter-sections of 160 acres and sixteen sections of 40 acres. The answer to the original question would be that a section, in this context, is b) A square typically one mile on a side. The geometric grid system established by the ordinance underlies much of the land division in the United States today.