Which statement most accurately represents Carnegie's effect on the steel industry between 1865 and 1892?

Andrew Carnegie (/kɑːrˈneɪɡi / kar-nay-gee, but commonly / ˈkɑːrnᵻɡi / kar-nə-gee or / kɑːrˈnɛɡi / kar-neg-ee; [4] November 25, 1835 - August 11, 1919) was a Scottish American industrialist who led the enormous expansion of the American steel industry in the late 19th century. He is often identified as one of the richest people and one of the richest Americans ever.[5] He built a leadership role as a philanthropist for the United States and the British Empire. During the last 18 years of his life, he gave away to charities, foundations, and universities about $350 million[6] (in 2015 share of GDP, $78.6 billion) - almost 90 percent of his fortune. His 1889 article proclaiming "The Gospel of Wealth " called on the rich to use their wealth to improve society, and it stimulated a wave of philanthropy.