What man could claim he was the richest man in the world at one time? andrew carnegie j. p. morgan henry blackwell john rockefeller

Option: Andrew Carnegie

Explanation:

Andrew Carnegie claimed to be the richest person in the world during the 19th century.  He was able to become one of the richest people in America by introducing the steel industry in America in the late 19th century. Carnegie Steel Company transformed steel production in the United States. While working in Railroad, he made good investment along with investing in oil which led him to open his company in America.

there are no mutiple choices here