<span>C) Most settlers were involved in farming in some way.</span>
The Great Wall is a fortificated East-to-West line which historically has delimited the Chinese Northern border. Its primary purpouse was to defend the Chinese territory against the invasions and quick raids organized by the nomadic people from the Eurasian Steppe lands, located more to the North.
But rather than as a fixed border, it should be regarded as a transition zone which establishes a distinction between two different lifestyles, even nowadays: the farmer regions in the South with sedentary ways of life and the pasture lands in the North, where its inhabitants have nomadic lifestyles and work mainly in animal husbandry activities.
Cultural: The Enlightenment philosophy desacralized the authority of the monarchy and the Catholic Church, and promoted a new society based on reason instead of traditions.
Social: The emergence of an influential bourgeoisie which was formally part of the Third Estate (commoners) but had evolved into a caste with its own agenda and aspired to political equality with the clergy (First Estate) and the aristocracy (Second Estate).
Financial: France's debt, aggravated by French involvement in the American Revolution, led Louis XVI to implement new taxations and to reduce privileges.
Political: Louis XVI faced strong opposition from provincial parlements which were the spearheads of the privileged classes' resistance to royal reforms.
Economic: The deregulation of the grain market, advocated by liberal economists, resulted in an increase in bread prices. In periods of bad harvests, it would lead to food scarcity which would prompt the masses to revolt.