You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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: When did the operation during which the 704th dropped supplies to allied troops near Nijmegen begin? Passage 1: The group was occasionally diverted from strategic missions to carry out air support and interdiction missions. It supported Operation Overlord, the invasion of Normandy by attacking transportation targets, including bridges, along with airfields and strong points in France. On D Day, the squadron and the rest of the 446th Group led the first heavy bomber mission of the day. The 446th aided ground forces at Caen and Saint-Lô during July by hitting bridges, gun batteries, and enemy troops. During Operation Market Garden, the attempt to seize a bridgehead across the Rhine in the Netherlands, the 704th dropped supplies to allied troops near Nijmegen. It struck lines of communications during the Battle of the Bulge. During Operation Varsity in March 1945, it supplied ground and airborne troops near Wesel. The squadron flew its last combat mission on 25 April 1945 against Salzburg, Austria. The group had flown 273 missions and had lost 58 aircraft during the war,
. Passage 2: John Ford (1894–1973) was an American film director whose career spanned from 1913 to 1971. During this time he directed more than 140 films. Born in Maine, Ford entered the filmmaking industry shortly after graduating from high school with the help of his older brother, Francis Ford, who had established himself as a leading man and director for Universal Studios. After working as an actor, assistant director, stuntman, and prop man – often for his brother – Universal gave Ford the opportunity to direct in 1917. Initially working in short films, he quickly moved into features, largely with Harry Carey as his star. In 1920 Ford left Universal and began working for the Fox Film Corporation. During the next ten years he directed more than 30 films, including the westerns The Iron Horse (1924) and 3 Bad Men (1926), both starring George O'Brien, the war drama Four Sons and the Irish romantic drama Hangman's House (both 1928 and both starring Victor McLaglen). In the same year of these last two films, Ford directed his first all-talking film, the short Napoleon's Barber. The following year he directed his first all-talking feature, The Black Watch.
. Passage 3: Since the late 1970s, the central part of NYU is its Washington Square campus in the heart of Greenwich Village. Despite being public property, and expanding the Fifth Avenue axis into Washington Square Park, the Washington Square Arch is the unofficial symbol of NYU. Until 2008, NYU's commencement ceremony was held in Washington Square Park. However, due to space constraints, ceremonies are now held at the Yankee Stadium. Important facilities at Washington Square are the Elmer Holmes Bobst Library, designed by Philip Johnson and Richard Foster, who also designed several other structures, such as Tisch Hall, Meyer Hall, and the Hagop Kevorkian Center. When designing these buildings Johnson and Foster also set up a master plan for a complete redesign of the NYU Washington Square campus. However, it was never implemented. Other historic buildings include the Silver Center (formerly known as "Main building"); the Brown Building of Science; Judson Hall, which houses the King Juan Carlos I of Spain Center; Vanderbilt Hall, the historic townhouse row on Washington Square North; The Grey Art Gallery at 100 Washington Square East, housing the New York University art collection and featuring museum quality exhibitions; the Kaufman Management Center; and the Torch Club – the NYU dining and club facility for alumni, faculty, and administrators. Just a block south of Washington Square is NYU's Washington Square Village, housing graduate students and junior and senior faculty residences in the Silver Towers, designed by I. M. Pei, where an enlargement of Picasso's sculpture Bust of Sylvette (1934) is displayed.
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Solution: 1
Why? The question refers to the 704th unit and task about war which is decribed by Passage 1.

New input: Question: How many times did Kathryn Day perform at the Metropolitan Opera House? Passage 1:The conflict emerged from the First Indochina War against the communist-led Viet Minh. Most of the funding for the French war effort was provided by the U.S. After the French quit Indochina in 1954, the US assumed financial and military support for the South Vietnamese state. The Việt Cộng, also known as or NLF (the National Liberation Front), a South Vietnamese common front under the direction of North Vietnam, initiated a guerrilla war in the south. North Vietnam had also invaded Laos in the mid-1950s in support of insurgents, establishing the Ho Chi Minh Trail to supply and reinforce the Việt Cộng. U.S. involvement escalated under President John F. Kennedy through the MAAG program from just under a thousand military advisors in 1959 to 16,000 in 1963. By 1963, the North Vietnamese had sent 40,000 soldiers to fight in South Vietnam. North Vietnam was heavily backed by the USSR and the People's Republic of China. China also sent hundreds of PLA servicemen to North Vietnam to serve in air-defense and support roles.
 Passage 2:Born in Philadelphia, Day studied at the Jacobs School of Music at Indiana University and at the Curtis Institute of Music where she was a pupil of Margaret Harshaw. She placed third in the finals of the Metropolitan Opera National Council Auditions in 1973, which led to her debut performance at the Metropolitan Opera House on March 25, 1973 singing "Come scoglio" from Così fan tutte and "Song to the Moon" from Rusalka. She made her professional opera debut in 1972 with the Pennsylvania Opera Company as Violetta in La traviata. That same year she was the soprano soloist in Verdi's Requiem with the Mendelssohn Club. In 1973 she portrayed Mimi in La bohème and Violetta with the Little Lyric Opera Company in Philadelphia. In 1974 she made her debut with the Philadelphia Lyric Opera Company as Nella in Gianni Schicchi.
 Passage 3:Stalybridge is a town in the Metropolitan Borough of Tameside in Greater Manchester, England. It lies on the course of the River Tame and the Huddersfield canal, on undulating land in the foothills of the Pennines. Historically a part of Cheshire, it is east of Manchester city centre and northwest of Glossop. The road from Oldham, to the pennine passes: the Snake pass and Woodhead, bridges the river at this point. Stalybridge was the junction of three early railway companies. The Ashton, Stalybridge and Liverpool Junction Railway Company was formed on 19 July 1844 and the railway was connected to Stalybridge on 5 October 1846. On 9 July 1847 the company was acquired by the Lancashire and Yorkshire Railway. On 1 August 1849 the Manchester, Stockport and Leeds Railway connected Stalybridge to Huddersfield and later to Stockport. This line later became part of the London and North Western Railway.

Solution:
2