The correct answer is (a) Adam Smith.
Adam Smith was a Scottish economist and philosopher who is considered the father of modern economics. He is best known for his book The Wealth of Nations, which was published in 1776. In this book, Smith argued that the wealth of a nation is not determined by the amount of gold and silver it possesses, but rather by the productivity of its people. He also argued that the free market is the best way to organize an economy, as it allows individuals to pursue their own self-interest, which in turn benefits society as a whole.
David Ricardo was an English economist who is considered one of the founders of classical economics. He is best known for his theory of comparative advantage, which states that countries should specialize in the production of goods in which they have a comparative advantage, and then trade with other countries for goods in which they have a comparative disadvantage.
J.M. Keynes was an English economist who is considered one of the most influential economists of the 20th century. He is best known for his work on macroeconomics, particularly his theory of aggregate demand and his role in the development of Keynesian economics.
Gunnar Myrdal was a Swedish economist and sociologist who is considered one of the most important social scientists of the 20th century. He is best known for his work on economic development and his theory of cumulative causation.