Please answer the following question: Klaus Wowereit (born 1 October 1953) is a German politician member of the SPD (Social Democratic Party) and has been the Governing Mayor of Berlin since the 21 October 2001 state elections where his party won a plurality of the votes 29.7%. He served as President of the Bundesrat (the fourth highest office in Germany) in 2001/02. 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