Given the question: Delta III-class submarine - The 667BDR Kalmar (Squid) Delta-III class submarine is a large ballistic missile submarine operated by the Russian Navy. Like other previous Delta class submarines the Delta III is a double hulled design with a thin low magnetic steel outer hull wrapped around a thicker inner pressure hull. Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
The answer is:
Mean Of Transportation