Given the task definition and input, reply with output. In this task, you're given a question, along with three passages, 1, 2, and 3. Your job is to determine which passage can be used to answer the question by searching for further information using terms from the passage. Indicate your choice as 1, 2, or 3.

Question: How old was Robert Nairac when Jones was promoted to lieutenant?  Passage 1:He has been a professor at Princeton since 1975, following a leave from his professorship at MIT. Lieb has been awarded several prizes in mathematics and physics, including the 1978 Heineman Prize for Mathematical Physics of the American Physical Society and the American Institute of Physics (1978), the Max Planck Medal of the German Physical Society (1992), the Boltzmann medal of the International Union of Pure and Applied Physics (1998), the Schock Prize (2001), and the Henri Poincaré Prize of the International Association of Mathematical Physics (2003). Lieb is a member of the U.S. National Academy of Sciences and has twice served (1982–1984 and 1997–1999) as the President of the International Association of Mathematical Physics. Lieb was awarded the Austrian Decoration for Science and Art in 2002. In 2012 he became a fellow of the American Mathematical Society and in 2013 a Foreign Member of the Royal Society.
 Passage 2:He was promoted to lieutenant on 23 January 1962, captain on 23 July 1966, and major on 31 December 1972, At this time he was brigade major at HQ 3rd Infantry Brigade in Northern Ireland. As such he was responsible for the efforts to find Captain Robert Nairac who had been abducted by the Provisional IRA. Nairac and Jones had become friends and would sometimes go to the Jones household for supper. After a four-day search, the Garda Síochána confirmed that Nairac had been shot and killed in the Republic of Ireland after being smuggled over the border. On 13 December 1977 he was appointed a Member of the Order of the British Empire (MBE) for his services in Northern Ireland that year. On 30 June 1979 he was promoted lieutenant colonel, and on 1 December 1979, he was transferred to the Parachute Regiment. In the 1981 New Year Honours he was appointed an Officer of the Order of the British Empire (OBE).
 Passage 3:In 1919, after the end of the war, he started his writing career. He wrote a polemical work entitled "The Knight, death and the devil: the heroic idea", a reworking of the tradition of German Pagan-Nationalist Romanticism into a form of "biological nationalism". Heinrich Himmler was very impressed by this book. In 1922 Günther studied at the University of Vienna while working in a museum in Dresden. In 1923 he moved to Scandinavia to live with his second wife, who was Norwegian. He received scientific awards from the University of Uppsala and the Swedish Institute for Race Biology, headed by Herman Lundborg. In Norway he met Vidkun Quisling. In May 1930 he was appointed to the University of Jena by Wilhelm Frick who had become the first NSDAP minister in a state government when he was appointed minister of education in the right-wing coalition government formed in Thuringen following an election in December 1929. In 1935 he became a professor at the University of Berlin, teaching race science, human biology and rural ethnography. From 1940 to 1945 he was professor at Albert Ludwigs University.
2