You will be given a definition of a task first, then some input 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: How old was the engineer who built Fort Mercer when it was built? 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.

Output:
3