Final answer:
Option (c), An eighteenth-century American colonist is the most likely to refer to the three regions of American colonies, recognizing the distinct differences in New England, the Mid-Atlantic, and the Southern colonies.
Step-by-step explanation:
The individual most likely to refer to the three regions of American colonies would be an eighteenth-century American colonist (c). This period was marked by a growing awareness of regional differences among the colonies due to their distinct economic foundations, social structures, and political developments. The three regions commonly recognized were New England, the Mid-Atlantic, and the Southern colonies.
An eighteenth-century American colonist would be living during the time when these regional identities were becoming more pronounced, especially leading up to and during the events that culminated in the American Revolutionary War.