The correct answer is D.
The Bessemer process was the first inexpensive method by making steel. It was invented by Henry Bessemer in 1856. The main idea was to remove impurities from the iron by oxidation. This invention helped the massive production of steel.
The Brooklyn Bridge's construction was possible because of Bessemer's invention. It was the world's first steel-wire construction bridge and the first crossing across the East River. The construction of the Bridge started in 1869.
