Given the task definition, example input & output, solve the new input case.
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.
Example: 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
Output: B
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 case for you: Article: For many years people in Estonia have been leaving their rubbish in the forests. Rainer Nolvak, a businessman and his friends wanted to clean up all the rubbish in Estonia. The rubbish was not just an environmental problem. It was a problem of people's attitudes. Rainer Nolvak got together with a team of 20 friends and they began to make a plan about how to clean up the rubbish. Soon, over 600 people joined in the group. They named the project Let's Do It! Estonia. The Ministry of the environment gave them some support. Many other companies joined in the group. Famous actors and singers also took part. Even the President of Estonia joined in. They sent information about Let's Do It! Estonia throughout the country. Technology experts developed a special computer program. Team members went into the forests to find where the rubbish was. They used their mobile phones to mark every place where they found rubbish and send the information to the computer program. Then, the marked rubbish places appeared on the map. Anyone could go on the Internet and see the map. The team found a surprising result. There were over 10,000 tons of waste in the forests of Estonia. When people saw how much waste was around their own homes, they were shocked. Thousands of people began to help. The team chose May 3, 2008 as the day to clean up the rubbish. On May 3, more than 50,000 people helped to get rid of the rubbish. They moved over 10,000 tons of rubbish in only one day! This was amazing for the environment in Estonia. But it was also an important step for Estonian society. Rainer Nolvak gave a speech at a conference in the Balkans. He said: "The most important thing we did was build a team. It changed every one of us. We had to connect to people. We had to see that the rubbish was our problem. At times we are afraid of sharing. When we are together and there are many of us, we are not afraid.'
Question: The Project Let's Do It! Estonia is to _ .
Options: (A) prevent people leaving their rubbish anywhere (B) make Estonia a clean place (C) change people' s attitudes towards the environment (D) make plans for businessmen
Output:
B