Who theorized that natural economic forces would keep wages at a survival level for workers?

The correct answer is David Ricardo. He is known for formulating the "iron law of wages," which posits that in a competitive labor market, the wages of workers tend to stabilize at a level necessary for basic survival. This theory suggests that economic forces, such as supply and demand for labor, dictate wages, leading to a scenario where increases in wages beyond this subsistence level would result in higher birth rates, thus eventually driving the wages back down to the survival level.

Ricardo's ideas were significant during the Industrial Revolution, as they presented a perspective on labor economics that underscored the struggles of workers at that time. His work contributed to discussions about labor rights and the conditions faced by working-class individuals in an industrializing society.

Other figures mentioned had different focuses: Thomas Malthus concentrated on population growth and its relation to resources; Adam Smith is primarily recognized for principles of capitalism and the "invisible hand" guiding markets; Robert Owen was a social reformer advocating for improved working conditions and cooperative societies rather than a theorist of wage dynamics. Thus, David Ricardo's economic analysis specifically addresses the relationship between wages and natural economic forces, solidifying his position as the correct answer.