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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: They tell us when to get up or when we're running late for work and whether we are in danger of missing our favourite TV programme. But while our daily routines rely on clocks that tell us the time, science is discovering that our well-being is influenced by a very different kind of timepiece. Circadian rhythms---the human body's own internal clock---have a powerful influence on our health and behaviour. _ are programmed from birth and control functions ranging from temperature and blood pressure to sleep patterns. In recent years researchers have also discovered that this built-in mechanism can influence everything from the way we react to medicines to how well we learn music. The latest example, from experts at Harvard University in the US, shows that the human body clock can even dictate whether or not we are likely to tell the truth. Researchers found it was easier for people to fib in the afternoon because, as they were tired, the self control that would normally prevent them from lying started to break down. Tiredness made it harder to resist the temptation to tell lies---especially if it meant they got a financial reward at the end. "The body clock has a great effect on us all," says Professor Jim Horne from the Sleep Research Centre at Loughborough University. "Most people tend to feel good around late morning and then decline in the early afternoon. But the time most of us will feel our sharpest is between 6pm and 8pm. That's because sleepiness tends to build up throughout the day. By early evening our body clock kicks in to wake us up. One reason may be to ensure we get home safely. When our ancestors were coming home after hunting all day their internal clocks kicked in to get them home in one piece." So what effects do circadian rhythms have and what's the best time of day to take advantage of them?
Question: According to the passage, when are people most quick-thinking?
Options: (A) In the morning. (B) Around midday. (C) In the late afternoon. (D) In the early evening.
Solution:
D