Please answer the following question: Mars 3 - Mars 3 was an unmanned space probe of the Soviet Mars program which spanned the years between 1960 and 1973. Mars 3 was launched nine days after its twin spacecraft Mars 2. The probes were identical spacecraft each consisting of an orbiter and an attached lander. After Mars 2 crash-landed on the martian surface Mars 3 lander became the first spacecraft to attain soft landing on Mars. Both probes were launched by Proton-K rockets with Blok D upper stages. 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?
A:
Mean Of Transportation