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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.

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
Solution: B
Why? 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.

New input: Article: As the nights get lounger, those who suffer from the winter blues will be planning ways to escape to the sunshine. But there may be a much simpler way of cheering yourself up... simply shining a bright light into your ear canal. Up to one in four Britons suffer from seasonal affective disorder, with seven per cent of the population having full-blown SAD. It is caused by the brain not receiving enough daylight which is needed to trigger serotonin , a hormone that regulates mood. Symptoms range from mild lethargy to depression and insomnia, but a cure might be in sight. Two clinical trials, run by Valkee - who make a device that can shine light into your ear - and the University of Oulu in Finland, have found that carefully targeted light can help prevent the condition. Juuso Nissila, Valkee's co-founder and chief scientist said: "We presented earlier that the human brain is sensitive to light". "These two clinical trials demonstrate that channeling bright light via ear canal into brain's photosensitive areas effectively prevents and treats seasonal affective disorder." The University of Oulu reported that in their first study, 92 per cent of the patients with seasonal affective disorder achieved full remission after a month of daily eight-to-12 minute doses of light from the Valkee. Time Takala, chief physician at the Oulu Deaconess Institute said: "These two trials show that bright light channeled into the brain via ear canal is an important future method to treat seasonal affective disorder." Valkee launched its bright light headset in August 2010. It is classed as a medical device under EU regulations. The device channels bright light direct to the brain via the ear canal to prevent and cure depression, mood swings and even circadian-rhythm disorders such as jet lag. It costs PS185 and looks like an iPod - only the earphones emit light rather than sound.
Question: How many Britons suffer from seasonal affective disorder?
Options: (A) Approximately a quarter. (B) 7%. (C) More than one fourth. (D) 92%.
Solution:
A