South Improvement Company was one part of which oil magnate's attempts to control this industry?
South Improvement Company:  It was created by major railroad interests, but was widely seen as part of John D. Rockefeller's early efforts to organize and control the oil and natural gas industries in the United States which eventually became Standard Oil. John D. Rockefeller: John Davison Rockefeller Sr. (July 8, 1839 – May 23, 1937) was an American oil industry business magnate and philanthropist.
John Davison Rockefeller Sr.