What new development made steel stronger and cheaper?

A Vertical integration
B Morrill acts
C Bessemer Process
D Mass production

C Bessemer Process

Is that the right answer

Yes, the correct answer is C) Bessemer Process. The Bessemer Process was a new development in the production of steel that involved blowing air through molten iron to remove impurities, resulting in a stronger and cheaper steel. This process revolutionized the steel industry and made steel production more efficient and cost-effective.