Please answer the following question: Vincent Francis Vince Callahan Jr. (born October 30 1931 in Washington D.C.) is an American politician who served for 40 years as a member of the Virginia House of Delegates. From January 1968 to January 2008 he represented the 34th district which covers McLean Great Falls Tysons Corner and parts of Herndon and Vienna. At the time of his retirement he was the longest-serving Republican in the Virginia General Assembly. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
A:
Office Holder