Ukishima Maru was a Japanese naval transport vessel. She was originally built as a passenger ship in March 1937. During World War II she served as a naval vessel after receiving heavy armament. She measured 4731 gross register tons. 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:
Mean Of Transportation