Duane Sand (born May 8 1965) is a North Dakota politician a graduate of the United States Naval Academy and a U.S. Navy officer during the Iraq War. Sand ran for the United States Senate in North Dakota on the Republican ticket in 2000 against incumbent Kent Conrad of the Democratic-Nonpartisan League and was called for duty after the election in 2001. Upon returning he ran for North Dakota's lone House seat in 2004 and 2008 but failed both times to defeat incumbent Earl Pomeroy. 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