Who used the technique of horizontal integration to dominate the american steel industry in the late 1800s?

Andrew Carnegie

Andrew Carnegie was a Scottish-American industrialist, business magnate and philanthropist. Carnegie was one of the richest people in history, thanks to his Carnegie Steel Company. The company is one of the earliest examples of vertical integration, as it controlled the mills where steel was made, the mines where the iron ore was extracted, the coal mines that supplied the coal, the ships and railroads that transported it, etc.

the real answer is b

she will pay the extra amount