Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Question: How many men served in the rifle division in which Ostashenko served as an assistant platoon commander? Passage 1:Ostashenko was born on 19 June 1896 in the village of Bolshaya Lyubshchina, Yanovichskoy volost, Vitebsky Uyezd, Vitebsk Governorate to a peasant family. He graduated from four grades at a gymnasium. During World War I, he was mobilized for military service on 7 August 1915, being sent to the 4th Company of the Reserve Battalion of the Petrograd Lifeguard Regiment in Petrograd. With the battalion, he fought with the Southwestern Front between July 1916 and February 1917, then returned to Petrograd before being demobilized on 13 March 1918. In July, he volunteered for the Red Army, serving in the Vitebsky Uyezd military commissariat as a clerk and instructor organizer. From May 1919 Ostashenko served as a Red Army man and political soldier – a Communist mobilized to conduct political work in the army – in the march battalion of the Vitebsk Reserve Regiment. From July he served as an assistant platoon commander in the 84th Rifle Regiment of the 10th Rifle Division, which fought against the Northwestern Army near Petrograd as part of the 15th Army of the Western Front. He entered the Smolensk Commanders' Infantry Courses in November and upon graduation in June 1920 became a platoon commander in the Rzhev-based 2nd Reserve Regiment. This assignment proved to be brief and a month later, Ostashenko became adjutant of the 4th Landing Detachment for armored trains with the Western Front. He fought with the detachment, which provided landing parties for armored trains, in the Polish–Soviet War and was wounded twice.
 Passage 2:Born Michael Sean Brotherton in Granite City, Illinois, he grew up in St. Louis, Missouri where he graduated from the John Burroughs School in 1986. He then headed south for college attending Rice University, from where he graduated Magna Cum Laude in 1990 with a BS in electrical engineering. He remained in Texas, going to the University of Texas at Austin for graduate work in astronomy where he specialized in studying quasars under Dr. Beverly Wills, earning his PhD in 1996. From 1996 to 1999 he was a postdoctoral fellow at the Institute of Geophysics and Planetary Physics at Lawrence Livermore National Laboratory working primarily with Wil van Breguel and Robert Becker on the Very Large Array's FIRST survey related projects. From 1999-2002, he was a postdoctoral researcher at the National Optical Astronomy Observatory and FUSE Science Team Associate working with Richard Green in Tucson, Arizona. He is currently a tenured professor of astronomy at the University of Wyoming at Laramie, where he's been since 2002.
 Passage 3:The Battle of Lexington and Concord was the first conflict in the American Revolutionary War. On April 19, 1775, a force of British Army regulars marched from Boston to Concord to capture a cache of arms that was reportedly stored in the town. Forewarned by Samuel Prescott (who had received the news from Paul Revere), the colonists mustered in opposition. Following an early-morning skirmish at Lexington, where the first shots of the battle were fired, the British expedition under the command of Lt. Col. Francis Smith advanced to Concord. There, colonists from Concord and surrounding towns (notably a highly drilled company from Acton led by Isaac Davis) repulsed a British detachment at the Old North Bridge and forced the British troops to retreat. Subsequently, militia arriving from across the region harried the British troops on their return to Boston, culminating in the Siege of Boston and the outbreak of the war.

Student:
1