Robert Cosgrove -  Sir Robert Cosgrove KCMG (28 December 1884 – 25 August 1969) was an Australian politician trade unionist and twice Premier of Tasmania from 18 December 1939 to 18 December 1947 and 25 February 1948 to 26 August 1958.His eighteen years as premier remains the longest in Tasmania's history; he dominated the state's Australian Labor Party branch for a generation.He was minister administering the Hydro-Electric Commission Act for sixteen years between 1942 and 1958He was married to Dame Gertrude Cosgrove from 1911 until her death in 1962; they had four children including a son who was killed in World War II; another son Henry Cosgrove became a Judge of the Supreme Court of Tasmania.  Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
Answer:
Office Holder