Final answer:
Thomas Jefferson maintained the lifestyle of an ordinary citizen as president and took pride in doubling the size of the U.S. through the Louisiana Purchase, reinforcing his agrarian vision.
Step-by-step explanation:
The statement that best describes how Thomas Jefferson related to his countrymen as president is that he maintained the lifestyle of an ordinary citizen and took pride in doubling the size of the United States territories. Jefferson promoted agriculture and envisioned a rural republic of land-owning White men, or yeoman republican farmers. He championed the rights of states, insisted on limited federal government and taxes, and is credited with the Louisiana Purchase in 1803, which doubled the nation's size and significantly advanced his vision of an agrarian society.