TASK DEFINITION: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
PROBLEM: Context: In the county, the population was spread out with 23.5% under the age of 18, 7.8% from 18 to 24, 28.5% from 25 to 44, 25.9% from 45 to 64, and 14.2% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 93.8 males. For every 100 females age 18 and over, there were 90.5 males. 
 Question: Which age group had the third most people?

SOLUTION: under the age of 18

PROBLEM: Context: Hans Ernst von Kottwitz (1 September 1757 -- 13 May 1843) was a German Pietist and philanthropist. 
 Question: What was Hans Ernst von Kottwitz's nationality?

SOLUTION: german

PROBLEM: Context: Academy-bus driver Jang Kyung-chul happens upon Jang Joo-yun one snowy night and offers to help fix her flat tire. Kyung-chul kills her and scatters her body parts. When a boy discovers one of Joo-yun's ears, the police are called in under the command of Section Chief Oh and Squad Chief Jang, the latter of whom is the father of Joo-yun. Kim Soo-hyun, a secret service agent of the National Intelligence Service (NIS) and Joo-yun's fiance, vows to track down and take vengeance on Joo-yun's murderer. Jang supplies Soo-hyun with a list of four suspects, including Kyung-chul. Searching Kyung-chul's home, Soo-hyun finds jewelry and underwear taken from (apparently) numerous victims. The discovery of Joo-yun's engagement ring proves that Kyung-chul is the killer. Soo-hyun puts a tracking device on the academy bus, following then attacking Kyung-chul while he is sexually assaulting his latest victimone of the schoolgirls he was transporting home. Beating him unconscious, Soo-hyun places an NIS transmitter inside Kyung-chul, allowing him to track him on radar and listen to his conversations. Waking up, Kyung-chul flags down a taxi. During the ride, Kyung-chul realizes that the two men in the cab are thugs looking to rob and possibly kill him; he stabs both men to death. After finding the real taxi driver in the trunk, Kyung-chul disposes of all three bodies before going to a medical center, where he attempts to sexually assault a nurse Han Song-yi. Soo-hyun intervenes and slashes Kyung-chul's Achilles tendon before letting him go again. Kyung-chul goes to the home of his friend Tae-joo, a cannibalistic murderer. After explaining his situation, Tae-joo remarks that whoever is after him must have some relation to one of his victims. Soo-hyun arrives, proceeding to incapacitate both murderers along with Tae-joo's girlfriend Se-jung. The next day, both Tae-joo and Se-jung are found by the police and sent to a hospital. A trusted subordinate of Soo-hyun's ensures he and Kyung-chul are sent to a private medical area away from the police. The barely conscious Kyung-chul hears them talk about the transmitter inside him. Soo-hyun dumps Kyung-chul, intending to continue stalking him. Kyung-chul taunts him over the transmitter, now knowing who he is. Kyung-chul brutally assaults a store owner, forcing Soo-hyun to rush to the aid of the victim. Kyung-chul uses this time to defecate out the transmitter and place it inside a taxi driver he viciously assaults. Soo-hyun interrogates Tae-joo and learns that Kyung-chul is going after Joo-yun's father Jang and sister Jang Se-yun. Soo-hyun arrives too late to stop Kyung-chul, who blinds Jang with a dumbbell and mutilates Se-yun. He abducts Kyung-chul before he can turn himself over to the police. Soo-hyun tortures him physically and mentally before setting up a guillotine above Kyung-chul's head that is soon activated when his parents and son arrive to visit and open the door to the room he is in. Placing a transmitter nearby, Soo-hyun's hears the death of Kyung-chul and his family's reaction to his decapitated corpse. Alternating between sobbing and fits of laughter, Soo-hyun suffers a mental breakdown while walking away from the house. 
 Question: Who vows to catch Kyung-chul after her kills his fiance?

SOLUTION:
kim soo-hyun