The correct answer is D) it shot air into the molten iron, making it hotter and eliminating impurities.
The Kelly-Bessemer process help make iron and steel production better in that it shot air into the molten iron, making it hotter and eliminating impurities.
This presented represented a great advantage in the production of steel because industries save money to fabricate it in large quantities. English engineering Henry Bessemer was the inventor of the process in 1850 but a similar invention was also developed by William Kelly in 1857. Both inventors worked hard to obtain a cheaper way to produce steel. They injected air into crude iron so the oxygen could"clean" the iron of its impurities.