Given the task definition and input, reply with output. 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: Who was the first commander of the military unit Cyril Isaac served in during world war 1? Passage 1: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.
 Passage 2: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 3:Colonel (promoted to Major General 4 June 1940) Mikhail Shumilov took command in April 1938. In September 1939, the corps fought in the Soviet invasion of Poland as part of the 10th Army. It included the 6th, 33rd, and the 121st Rifle Divisions at the beginning of the invasion on 17 September. By 2 October, these divisions had transferred to other units, and it included the 29th, 64th, and 145th Rifle Divisions instead. The corps headquarters relocated to Grodno in November and became part of the 11th Army. Between June and July 1940 it was briefly headquartered at Kovno before moving to Šiauliai in August, part of the Baltic Special Military District. The 11th transferred to the 8th Army in October, and included the 11th and 125th Rifle Divisions by the outbreak of the war. It defended a 40-kilometer sector on the left flank of the 8th Army, with its headquarters in the forests northwest of Skaudvilė. The 125th Rifle Division was in the corps' first echelon, holding covering the highway and railroad from Tilsit to Šiauliai. The 48th Rifle Division (part of the adjacent 10th Rifle Corps), after moving forward from Riga, was to take up positions on the left of the 125th. The corps' 73rd Corps Artillery Regiment included four battalions of 107 mm guns.
2