Final answer:
The Correct option is 2). Milton Friedman is the American economist associated with monetarism, advocating for minimal government intervention in the economy and influencing the U.S. free enterprise system.
Step-by-step explanation:
The American economist who identified with monetarism is Milton Friedman. Monetarism is an economic philosophy that emphasizes the role of governments in controlling the amount of money in circulation. Milton Friedman, who was a strong advocate for free-market capitalism, argued that government intervention should be minimal and believed that the Federal Reserve Bank's interference often led to economic instability. Instead, he supported the idea that the money supply should grow proportionally with the economy itself.
John Maynard Keynes, in contrast, advocated for increased government intervention during economic downturns. Adam Smith is famous for his invisible hand theory, promoting free-market capitalism, while Karl Marx is known for his critique of capitalism and advocacy for socialism. Friedman's ideas have been influential in shaping the current U.S. free enterprise system, favoring minimal government intervention in the economy.