Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. German submarine U-210 -  The German submarine U-210 was a Type VIIC U-boat that served with the Kriegsmarine during World War II. Laid down on 15 March 1941 as 'werk 639' at F. Krupp Germaniawerft in Kiel she was launched on 23 December and commissioned on 21 February 1942.
Answer:
Mean Of Transportation