In this task, you're given an article, a question which often contains a blank and four options (associated with "A", "B", "C", "D"). Your task is to find the correct answer (from the given options) for the question from the given article and return one of the options from "A", "B", "C", and "D". Do not generate anything else apart from one of the following characters: "A", "B", "C", "D". There is only one correct answer for each question.
Example: Article: Homework can put you in a bad mood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay.
Question: Researchers did experiments on kids in order to find out _ .
Options: (A) how they really feel when they are learning (B) whether mood affects their learning ability (C) what methods are easy for kids to learn (D) the relationship between sadness and happiness
Example solution: B
Example explanation: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment. So, B is the correct answer.

Problem: Article: "Eat local." It's one way to reduce human effect on the planet.Eating local means to try to buy and consume foods that are grown in places close to home.However, most of the food sold at supermarkets is not locally grown or produced.Trucks and planes deliver these foods from hundreds or thousands of miles away.During the transportation, greenhouse gases are produced, causing global warming.So the shorter the distance your foods must travel, the less the harm is done to the environment. But how do you get local food if you live in a large city, hundreds of miles away from farms?Environmental health scientist Dickson Despommier and his students came up with the idea of a "vertical farm". A vertical farm is a glass-walled structure that could be built as tall as a skyscraper.Since the garden is built upwards, rather than outwards, it requires much less space than an ordinary farm.The world is quickly running out of room for ordinary farming.Vertical farms could be a key to this situation.Despommier imagines a 30-story building with a greenhouse on every floor.The walls of the building would be clear, to allow crops to get as much sunlight as possible.Depending on a city's water resources, Despommier thinks hydroponic farming is another method for the vertical farm which needs no soil to grow plants. Despommier says the hydroponic greenhouses would use a system that would use a city's waste water and fill it with nutrition to make the crops grow.If this method works, it would provide food to a city and save millions of tons of water. The idea of a vertical farm has attracted the attention of government officials around the world.Scott Stringer, a government official from New York City, thinks the city is suitable for the vertical farming."Obviously we don't have much land left for us," Stringer said, "But the sky is the limit in Manhattan." Despommier admits that there is still a lot of work to do to make vertical farms a reality."But I think vertical farming is an idea that can work in a big way." he says.
Question: Why are people advised to eat local?
Options: (A) Because it means convenience to people. (B) Because it can help people save a lot of money. (C) Because local food has more nutrition. (D) Because it is environmentally friendly.
Solution: D