Given the question: 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. Titan 23G - The Titan 23G Titan II(23)G Titan 2(23)G or Titan II SLV was an American expendable launch system derived from the LGM-25C Titan II intercontinental ballistic missile. Retired Titan II missiles were converted by Martin Marietta into which the Glenn L. Martin Company which built the original Titan II had merged. It was used to carry payloads for the United States Air Force NASA and NOAA.
The answer is:
Mean Of Transportation