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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: Industrial pollution is not only a problem for the countries of Europe and North America but also an extremely serious problem in some developing countries. For these countries, economic growth is a very important aim. They want to introduce industries, and so they put few controls on the industries which cause pollution. Cubatao, an industrial town of 85 000 people in Brazil, is an example of the connection between industrial development and pollution. In 1954, Cubatao had no industry. Today it has more than twenty large factories, which produce many pollutants . The people of the town are suffering from the poisonous matter in their environment and the bad effects can be clearly seen. Birth shortcomings are extremely common. Among children and adults, lung problems are sometimes twelve times more common in Cubatao than in other places. It is true that Brazil, like many other countries, has laws against pollution, but these laws are not enforced strictly enough. It is cheaper for companies to take no notice of the laws and pay the fines than to buy the expensive equipment that will reduce the pollution. It is clear, therefore, that economic growth is more important to the government than to the health of the workers. However, the responsibility does not completely lie with the Brazilian government. The example of Cubatao shows that international companies are not acting in a responsible way either. A number of the factories in the town are owned by large companies from France, Italy, and the U. S. They are doing things in Brazil that they would not be able to do at home. If they caused the same amount of pollution at home, they would be severely punished or even put out of business.
Question: Why don't developing countries have strict pollution controls?
Options: (A) The new industries they want to introduce do not cause much pollution. (B) Pollution is not a serious problem for developing countries. (C) They don't realize the balance of nature will be destroyed by some pollutants. (D) If they put stricter controls on industry, fewer companies would build new plants in developing countries.
Solution:
D