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 General Sir William Robertson when he selected Hugh Elles to liasise with troops? Passage 1:He was born in Brunswick to Congregationalist minister Abraham Isaac and Mary Judd. He attended state schools and became a schoolteacher, working for the Victorian Education Department from 1900. On 3 September 1907 he married Elizabeth Brown, with whom he had four children. In 1913 he was appointed a supervisor of school gardening, and pioneered several early initiatives in this area. During World War I he served with the 58th Battalion, and after the war he spent time in England studying horticulture. He ran a nursery at Noble Park from 1922. From 1928 to 1931 and 1937 to 1940 he was a member of Dandenong Shire Council, and he was also chairman of Associated Nurseries Pty Ltd from 1932 to 1965 and president of the Nurserymen and Seedsmen's Association from 1936 to 1937. In 1940 he was elected to the Victorian Legislative Council as a United Australia Party member for South Eastern Province. While in the Council he ran a Save the Forests campaign, which evolved into the National Resources Conservation League in which Isaac played a leading role. He lost Liberal and Country Party endorsement in 1952 and was defeated running as an independent candidate. In 1956 he was appointed an Officer of the Order of the British Empire. Isaac died at Footscray in 1965.
Passage 2:In August 1915, after recovering from his injuries, Elles was one of three officers specially selected by General Sir William Robertson, soon to be Chief of the Imperial General Staff (CIGS), the professional head of the British Army, to liaise with troops at the front and pass the information directly to the British General Headquarters (GHQ). In January 1916, as a General Staff Officer (GSO), Elles was sent by General Sir Douglas Haig, the Commander-in-Chief (C-in-C) of the BEF on the Western Front, to investigate the first tanks or "caterpillars" being built in England. He attended the first trials of "Mother" and reported back to Haig on its success. During the summer of 1916, he was tasked to report back from the Somme, where the tanks were first used. Elles was appointed to head the Heavy Branch (the first tank units) of the Machine Gun Corps in France on 29 September 1916, with the temporary rank of colonel. His responsibilities included its advanced training and tactical employment. He also commanded the large central depot and workshops established near Bermicourt.
Passage 3:Matheson was born on April 7, 1949 in Winnipeg, Manitoba to Jack and Peggy Matheson. Matheson had an intention to follow the footsteps of his father, Jack, a long-time sports editor for the Winnipeg Tribune. He graduated from the University of Manitoba with a degree in political science, and while in school, worked a part-time night shift with the Tribune. He got his first job upon completing school with the Regina Leader-Post, but moved west to Edmonton, Alberta six months later. Upon moving to Edmonton, Matheson got a job with the Edmonton Journal in 1970. He initially covered local curling and university sports, but quickly switched to hockey, when, in 1973, Edmonton was granted a WHA franchise, the Edmonton Oilers. Matheson became the beat writer for the Oilers then, and continued when the Oilers joined the NHL in 1979. He spent countless hours covering the team and its five Stanley Cups, and completed more than 300 stories per winter. In addition to writing, Matheson also was a part of the CFRN radio broadcasting team that covered the Oilers. After 24 years, he completed his tenure as beat writer for the Oilers in 1997. He now continues to write for the Edmonton Journal covering the NHL and the Oilers.
2