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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: Maybe you've just invented something better than the iPhone or a solar-powered car. You don't want anyone to steal your design. What should you do? Patent it! Patents are the best way to get credit for your work and help others continue advancing in that field. Here's what you need to know. A patent gives you the right to an invention. The patent protects its owner, which means the invention can't be copied or sold without their agreement. In exchange, the owner must reveal information about the invention. This contributes knowledge that helps other inventors improve on their own research. A patent usually lasts about 20 years. The first step to getting a patent is the application. The person applying must name the invention, explain its use and describe it clearly. The invention must be practical and contain some new characteristic -- something that hasn't been seen or used before. But not everything "new" can be patented. Many countries don't allow patents on things like new concepts, scientific theories, medical procedures or substances already found in nature. You may not be able to see patents, but they're connected to nearly everything. There are patents on things you use every day, like plastic, medicine and your computer. There are patents on things that are unavailable on the market, too. Apple is well-known for its patents on potential products, such as the "iBike" or the "iKey". Of course there are also patents on inventions like this. Take the anti-eating face mask for example. This _ locks around your head with a metal cage covering your mouth. You can breathe and speak, but you can't eat! Although many patented inventions can be failures, there's plenty of room for success. So if you have a cool invention, try to patent it.
Question: Which of the following is NOT true according to the text?
Options: (A) A patent can last for around 20 years. (B) Everything new can be patented. (C) Your invention is protected after you have applied for a patent. (D) Some patents are on the things that we use every day.
Solution:
B