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.

[Q]: Context: A personal journey into the heart of the Killing FieldsOne of the most harrowing and compelling personal documentaries of our time, ENEMIES OF THE PEOPLE exposes for the first time the truth about the Killing Fields and the Khmer Rouge who were behind Cambodias horrific genocide. More than simply an inquiry into Cambodias experience, however, ENEMIES OF THE PEOPLE is a profound meditation on the nature of good and evil, shedding light on the capacity of some people to do terrible things and for others to forgive them.Winner of a dozen top documentary festival awards, including a Special Jury Prize at Sundance and the Grand Jury Award at the Full Frame Documentary Festival, this is a riveting film that takes audiences as close to witnessing evil as they are ever likely to get. It is also a personal journey into the heart of darkness by journalist/filmmaker Thet Sambath, whose family was wiped out in the Killing Fields, but whose patience and discipline elicits unprecedented on-camera confessions from perpetrators at all levels of the Khmer Rouge hierarchy. This is investigative journalism of the highest order.In 1974, Thet Sambaths father became one of the nearly two million people who were murdered by the Khmer Rouge when he refused to give them his buffalo. Sambaths mother was forced to marry a Khmer Rouge militiaman and died in childbirth in 1976, while his eldest brother disappeared in 1977. Sambath himself escaped Cambodia at age 10 when the Khmer Rouge fell in 1979.Fast forward to 1998, and Sambath, now a journalist, got to know the children of some senior Khmer Rouge cadre and gradually earned their trust. Then, for a decade, he spent weekends visiting the home of the most senior surviving leader, Nuon Chea, aka Brother Number Two under Pol Pot. But he never used to say anything different from what he told Western journalists, says Sambath, I was low-ranking, I knew nothing, I am not a killer. Then one day he said to me Sambath, I trust you, you are the person I would like to tell my story to. Ask me what you want to know. For the next five years he told me the truth, as he saw it, including all the details of killing.Sambath also won the confidence of lower-level Khmer Rouge soldiers, now ordinary fathers and grandfathers, who demonstrated to him how they slit peoples throats. For these murderers, it was the first time they admitted what they had done. He taped their interactions and discussions about the killings, and together with British documentarian Rob Lemkin they created this landmark film.For Sambath, it has been an ongoing, lifelong personal journey to discover what was behind such horror; he neglected both his family and his own happiness in the search for truth with hope of reconciliation. ENEMIES OF THE PEOPLE is at once a cinematically beautiful, chillingly insightful, and deeply personal piece of documentary filmmaking. 
 Question: How many Cambodians died during the rule of Khmer Rouge?
[A]: nearly two million


[Q]: Context: Modeled after US hot website.com, group buying websites are now popular in China. These websites use the power of group buying to get competitive discounts for a daily deal on some best stuff to do, see, eat and buy in the cities across China. Discounts are available within just one click. Zhao lei, a software engineer in Beijing, loves the one-hour lunch break at noon,as it is the best time for him to check "today's special" at his favorite group buying websites . Sometimes he searches for great deals at directory sites devoted to the new shopping space. Zhao spends around 800 yuan($117.65) on group buying every month, mostly to buy food coupons for eating at some nice restaurants and occasionally to find something fun to do. " I love group buying. In addition to the competitive discounts it offers, it helps me get something fun, exciting and new, and such surprises give me a reason to try something new," he said. When he finds a really good bargain, he will send the link to friends or colleagues through MSN,QQ, or e-mail, or share the information at some social networking websites. In doing so, he often gets a certain cut off the price. At some sites, buyers are invited to leave notes about what they want to buy and the website will consider it if similar applications reach a certain number. That is how Zuo got her digital camera after waiting for two months. "It is cool. I want to buy a new digitgal camera for my trip to Switzerland this winter, but I never expected such cheap prices!" Zuo said. 
 Question: What is the passage mainly about?
[A]: group buying


[Q]: Context: A magnet is an object that attracts certain materials such as iron. Youre probably familiar with common bar magnets, like the one shown in the Figure 1.1. Like all magnets, this bar magnet has north and south magnetic poles. The red end of the magnet is the north pole and the blue end is the south pole. The poles are regions where the magnet is strongest. The poles are called north and south because they always line up with Earths north-south axis if the magnet is allowed to move freely. (Earths axis is the imaginary line around which the planet rotates.) Q: What do you suppose would happen if you cut the bar magnet pictured in the Figure 1.1 along the line between the north and south poles? A: Both halves of the magnet would also have north and south poles. If you cut each of the halves in half, all those pieces would have north and south poles as well. Pieces of a magnet always have both north and south poles no matter how many times you cut the magnet. The force that a magnet exerts on certain materials, including other magnets, is called magnetic force. The force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other. A magnet can exert force over a distance because the magnet is surrounded by a magnetic field. In the Figure 1.2, you can see the magnetic field surrounding a bar magnet. Tiny bits of iron, called iron filings, were placed under a sheet of glass. When the magnet was placed on the glass, it attracted the iron filings. The pattern of the iron filings shows the lines of force that make up the magnetic field of the magnet. The concentration of iron filings near the poles indicates that these areas exert the strongest force. You can also see how the magnetic field affects the compasses placed above the magnet. When two magnets are brought close together, their magnetic fields interact. You can see how they interact in the Figure 1.3. The lines of force of north and south poles attract each other whereas those of two north poles repel each other. 
 Question: a magnets force is
[A]:
exerted over a distance.