Who invented a process that made steel production cheaper and more efficient?

The correct answer is Henry Bessemer. He invented the Bessemer process in the 1850s, which significantly transformed the steel industry. This process involved blowing air through molten iron to remove impurities, resulting in a much more efficient and cost-effective method of producing steel. Before Bessemer's innovation, steel was expensive to make and typically produced in small quantities. With his method, large quantities of steel could be produced quickly and at a lower cost, leading to the widespread use of steel in construction, manufacturing, and various industries during the Industrial Revolution.

Andrew Carnegie is often associated with the steel industry because of his successful business, but he was not the inventor of the process that revolutionized steel production. Thomas Edison is known primarily for his work in electricity and inventions, not specifically for steel production. John D. Rockefeller made his mark in the oil industry and is not linked to advancements in steel. Thus, Bessemer's contribution stands out as pivotal to the development of the steel industry.