Option 1: Adam Smith -> Known for 'The Wealth of Nations', not this work.
Option 2: David Ricardo -> Famous for 'Principles of Political Economy and Taxation'.
Option 3: J.S. Mill -> Authored 'Principles of Political Economy'.
Option 4: John Maynard Keynes -> Author of 'The General Theory of Employment, Interest and Money'.
Hence, Option 4: John Maynard Keynes -> This seminal work, published in 1936, revolutionized economic thought and laid the foundation for modern macroeconomics. Keynes challenged classical economic theories and introduced concepts like aggregate demand, the multiplier effect, and the role of government intervention during economic downturns. This book became the cornerstone of Keynesian economics -> correct