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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: A super drug that could remove Alzheimer's ,heart disease and diabetes and help people live to 100 is being developed by scientists. Their research is based on the identification of three genes that help prolong lives and prevent diseases which occur in old age. Medically controlling the proteins made by the " longevity genes" will allow millions to live longer, predicts Dr Nir Barzilai. Those whose DNA strongly features the three genes are 80 percent less likely to develop Alzheimer's. The genes also fight against the deadly impact of smoking, poor diet, obesity and lack of exercise. Already, several laboratories are working on a pill to imitate the benefits of the genes and Dr Barzilai thinks it could be tested within three years. The pill could remove some diseases that damage old age. " The advantage of finding a gene that involves longevity is that we can develop a drug that will imitate exactly what this gene is doing," he said. Of the three longevity genes, two genes increase the production of so-called good cholesterol , which reduces the risk of heart disease. The third prevents diabetes. They were discovered by Dr Barzilai's team while studying the DNA of 500 Ashkenazi Jews with an average age of 100. The chances of living that long are one in 10,000 but the group, which shared relatively few common ancestors, was 20 times more likely to hit the entury. Dr Barzilai said: " 30 percent of them were obese or overweight and 30 percent smoked two acks of cigarettes a day for more than 40 years, however they can live to 100." But Andrew Ketteringham of the Alzheimer's Society said: "Alzheimer's disease, a most common disease, is likely to be caused by a combination of genetic disosition , lifestyles and life events. Many genes are probably involved.
Question: Some people are able to live to 100 years because of _ .
Options: (A) a magical medicine (B) three special genes (C) good living habits (D) longevity proteins
Solution:
B