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.

Let me give you an example: 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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The answer to this example can be: 1
Here is why: The question refers to the 704th unit and task about war which is decribed by Passage 1.

OK. solve this:
Question: Who won the battle where Hugh Mercer was killed? Passage 1:The Calgary Flames selected him in the eighth round, 182nd overall at the 1981 NHL Entry Draft, and he began his professional career in 1983–84 with a 30-point season for the Colorado Flames of the Central Hockey League (CHL). He then spent the majority of three seasons in the American Hockey League (AHL) with the Moncton Golden Flames. He was named to the AHL second All-Star Team in 1984–85, and served as captain of the Golden Flames in 1985–86. DeGray appeared in one NHL game that season, making his NHL debut with Calgary on March 6, 1986, against the New York Rangers. He played a part-time role in Calgary in 1986–87; in 27 games with the Flames, DeGray scored six goals and seven assists.
 Passage 2:Mušicki was stationed in Slavonski Brod at the time of the Axis invasion of Yugoslavia in April 1941 and served as the Royal Yugoslav Army commander responsible for the railroad between Belgrade and Zagreb in the rank of colonel. He demonstrated his support for the Germans by helping their forces during the invasion. Yugoslavia was quickly conquered by the Axis powers and Mušicki remained in Slavonski Brod for several months after the conquest. He attempted to join the Ustaše Militia there, but was rejected. He went to Belgrade in mid-August, where he was received by Zbor leader Dimitrije Ljotić. On 6 October, Milan Nedić, the Prime Minister of the Axis-installed puppet Government of National Salvation, appointed Mušicki to lead the Serbian Volunteer Command (, SDK). Mušicki was involved in executing Serb civilians in the town of Čačak in December 1941. He and Milan Aćimović contacted Chetnik leader Draža Mihailović on 5 December, possibly in an effort to warn him in advance of the assault the Germans had planned, codenamed Operation Mihailovic. This action prompted the Germans to question Mušicki's loyalty. He was removed from command at the end of 1941 and imprisoned by the Germans, but was later freed at Nedić's intervention.
 Passage 3:Fort Mercer was a fort on the Delaware River in New Jersey constructed by the Continental Army during the American Revolutionary War. Built by Polish engineer Thaddeus Kosciuszko under the command of George Washington, Fort Mercer was built in 1777 to block the approach to Philadelphia, Pennsylvania in concert with Fort Mifflin on the Pennsylvania side. Fort Mercer was located in an area called Red Bank, in what is now the borough of National Park, Gloucester County, New Jersey. The fort was named in honor of Brigadier General Hugh Mercer who had died earlier that year at the Battle of Princeton. The fort's site is now part of Red Bank Battlefield Historical Park, which includes a monument and museum. Several cannons attributed to British warships lost supporting the attack on the fort, and others found buried at the fort itself, are in the park.

Answer:
3