The correct answer is: D. Jacob Viner
Jacob Viner was an American economist who is considered one of the most important figures in the history of economic thought. He is best known for his work on international trade, tariffs, and economic development.
The quote “Economics is what Economists do” is often attributed to Viner. In a 1925 article, Viner wrote: “Economics is what economists do. The subject matter of economics is whatever economists choose to make it.” This statement reflects Viner’s view that economics is a discipline that is constantly evolving and changing, as economists develop new theories and methods.
Adam Smith, Alfred Marshall, and R. W. Souter were all important economists, but they did not make the same statement about economics as Viner did. Smith is best known for his book “The Wealth of Nations,” which is considered one of the most important works of economic theory. Marshall is best known for his book “Principles of Economics,” which is considered one of the most influential textbooks in the history of economics. Souter is best known for his work on economic history.
In conclusion, the correct answer to the question “Economics is what Economists do” was stated by D. Jacob Viner.