d) Andrew Carnegie

Andrew Carnegie dominated the steel industry during the Gilded Age. Starting as a telegraph operator, Carnegie built a business empire that revolutionized the steel production process. His use of innovative technologies like the Bessemer process allowed for the mass production of steel, fueling America’s industrial growth. Carnegie’s business practices and philanthropy left a lasting impact on the American economic landscape and exemplified the mixture of innovation, entrepreneurship, and social issues of the Gilded Age.