Q: 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 long did the Pleiku Campaign take place? Passage 1:Behavioral neuroscience applies the principles of neurobiology, to the study of physiological, genetic, and developmental mechanisms of behavior. Cognitive inhibition is caused by several different interacting biological factors. The first is the existence of inhibitory neurotransmitters, or chemicals emitted by brain cells to both communicate and inhibit communication between each other. "GABA, an inhibitory transmitter substance that has been implicated in certain simple behavioral measures of inhibition and the control of aggressive behavior, was discovered in the cerebral cortex in substantial quantities". Given the cerebral cortex's importance in many brain functions such as memory and thought, the presence of the inhibitory substance GABA supports the cognitive inhibition processes that go on in this area of the brain. Serotonin and dopamine, which can play inhibitory roles as well, are present in the brain in large quantities. All three of these neurotransmitters are capable of "blocking" the transmissions between neurons, which can ultimately result in cognitive inhibition. In addition, the presence of inhibitory connections in the central nervous system has been firmly demonstrated (Eccles, 1969). A process known as lateral inhibition, which involves the capacity of an excited neuron to reduce the activity of its neighbors, is integral in the biology of cognitive inhibition. It provides much of the neural background behind it and explains what exactly is going on at the cellular level.
 Passage 2:The Battle of Ia Drang was the first major battle between the United States Army and the People's Army of Vietnam (PAVN), also referred to as the North Vietnamese Army (NVA), and was part of the Pleiku Campaign conducted early in the Vietnam War. It comprised two main engagements, centered on two previously scouted helicopter landing zones (LZs), known as LZ X-Ray and LZ Albany. The first involved the 1st Battalion, 7th Cavalry Regiment and supporting units under the command of Lieutenant Colonel Hal Moore, and took place November 14–16, 1965 at LZ X-Ray, located at the eastern foot of the Chu Pong Massif in the central highlands of Vietnam. The second engagement involved the 2nd Battalion, 7th Cavalry Regiment plus supporting units under the command of Lieutenant Colonel Robert McDade, and took place on November 17 at LZ Albany, farther north in the Ia Drang Valley. It is notable for being the first large scale helicopter air assault and also the first use of Boeing B-52 Stratofortress strategic bombers in a tactical support role. Surrounded and under heavy fire from a numerically superior force, the American forces at LZ X-ray were able to hold off and drive back the North Vietnamese forces over three days of battle, largely through the support of both air power and heavy artillery bombardment, which the North Vietnamese lacked. LZ X-ray was considered an American tactical victory, as the Americans were able to exact an almost 10:1 kill ratio. At LZ Albany, the American forces were ambushed in close quarters. They were unable to use air and artillery support due to the close engagement of the North Vietnamese, the American forces were badly defeated, suffering an over-50% casualty rate before being extricated from the battle. Both sides, therefore, were able to claim victory in the battle.
 Passage 3:The Dangerous Liaisons is an opera in two acts and eight scenes, with music by Conrad Susa to an English libretto by Philip Littell. It is based on the novel Les Liaisons dangereuses by Pierre Choderlos de Laclos. The opera has set numbers with recitative and spoken dialog. It is set in France in the 18th century. The opera received its first performance by the San Francisco Opera on 10 September 1994, with stage direction by Colin Graham and Donald Runnicles as the conductor. The world-premiere cast included Thomas Hampson as Valmont, Frederica von Stade as Merteuil, David Hobson as Chevalier de Danceny, Renée Fleming as Tourvel and Mary Mills as Cécile de Volanges. The opera was performed at Washington Opera in March 1998. It was also aired on the American PBS television network's Great Performances, a video recording of which was also made. Albany Records released an audio recording of a performance by Manhattan School of Music Opera Theater in 2016.

A:
2