The correct answer is: William J. Baumol.
William J. Baumol (1922-2017) was an American economist who is best known for his work on the theory of money and economic growth. He was a professor at Princeton University for over 50 years and served as the president of the American Economic Association in 1971.
In 1952, Baumol published a paper titled “The Transactions Demand for Cash: An Inventory Theoretic Approach.” In this paper, he proposed a model to apply the economic order quantity concept of inventory management to determine the optimum cash holding in a firm. This model, which is now known as the Baumol-Tobin model, is still widely used today.
The other options are incorrect. Keith V. Smith is a professor of finance at the University of California, Berkeley. Miller and Orr are two economists who developed a model to determine the optimal level of cash reserves for a firm. J. M. Keynes was a British economist who is considered one of the most influential economists of the 20th century. He is best known for his work on macroeconomics, including his theory of general equilibrium and his theory of liquidity preference.