Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Question: What country was the Us Army's Obersvation Post Alpha located in? Passage 1:The station opened on 29 November 1844 by the Dublin and Drogheda Railway Company as Dublin Station, but was renamed Amiens Street Station ten years later after the street on which it is located. Originally the station served only a single mainline to Drogheda, and in 1853 through services to Belfast commenced. In 1891, the City of Dublin Junction Railway connected the station with Westland Row Station (now Pearse Station) on the city's South side. The City of Dublin Junction had a separate station known as Amiens Street Junction consisting of the present platforms 5, 6, and 7 (currently used by DART, Commuter and Rosslare services) with a separate street entrance. After the amalgamation of the GNR (I) at the end of the 1950s, this station became part of Amiens Street and the separate entrance fell into disuse. The City of Dublin Junction Railway allowed services to run from Amiens Street through to Westland Row to Rosslare and the South East. Services to Sligo were transferred to Westland Row (Pearse Station) running non-stop through the station in 1937, with the closure of Broadstone Station by CIÉ (see also MGWR). Services to Galway and Mayo also terminated at Westland Row, operating through Connolly Station after 1937, running via Mullingar and Athlone. This was discontinued in the 1970s in favour of running services from Heuston Station. Sunday trains to Cork, Limerick and Waterford during the 1960s operated from Connolly platforms 5, 6 and 7 through the Phoenix Park Tunnel, so as to avoid the cost of opening Heuston for the limited Sunday traffic demand at that time.
 Passage 2:In June 1949, Arnstadt registered for service with the Volkspolizei, the police force of the Soviet Occupation Zone, becoming an Anwärter der VP (police cadet) with the Kasernierte Volkspolizei in Gotha. In March 1950, Arnstadt was appointed to the German Border Police (Deutsche Grenzpolizei) in Dermbach, patrolling the Inner German border with West Germany. In 1952, Arnstadt failed his first attempt to become an officer at the police school in Sondershausen. In 1953, his marriage ended in divorce, with his two children Veronika and Uwe staying with the mother, and remarried shortly after. In 1954, Arnstadt passed his officer training at Sondershausen and was appointed the rank of Unterleutnant, and the following year was promoted to lieutenant. Arnstadt functioned as a recruiter for the German Border Police until 1957 when he was appointed as a company commander of the 6th border company in Dermbach. Arnstadt was responsible for a section of the border at Wiesenfeld, a region of Bezirk Suhl in the Rhön Mountains at the westernmost point of the Warsaw Pact. Arnstadt's section contained the highly-strategic Fulda Gap, which aroused the special interest of NATO, and a short distance from the US Army's Observation Post Alpha. Arnstadt moved with his wife to Wiesenfeld and in April 1957 became an unofficial collaborator (Geheimer Informator) of the Ministry for State Security (Stasi) until this relationship was ended fourteen months later. 
 Passage 3:Frazier attended Oconee County High School in Watkinsville, Georgia, graduating in 2010. While playing for the school's baseball team, Frazier recorded 53 doubles, the second most in the history of the Georgia High School Association. Frazier enrolled at Mississippi State University to play college baseball for the Mississippi State Bulldogs. He played sparingly as a freshman. In 2012, his sophomore year, Frazier set a Mississippi State record for assists in a season (227) and was named the most valuable player of the Southeastern Conference (SEC) Baseball Tournament, and was chosen for the United States national collegiate baseball team. In 2013, his junior season, he led the National Collegiate Athletic Association with 107 hits, which set a Bulldogs single-season record, while also setting school records for assists (240) and putouts (120) in a season, and putouts over a career (375). He was named to the SEC All-Tournament Team.

Student:
2