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: Passengers will be able to travel by train from Londonto Beijing in just two days on trains that travel almost as fast as airplanes under new plans from China. China is under discussion with 17 countries to build a high-speed rail network to India and Europe with trains that are able to run at over 200mph within the next decade. The network would eventually carry passengers from London to Beijing and then to Singapore. It would also run to India and Pakistan, according to Wang Mengshu, a member of the Chinese Academy of Engineering and a senior consultant on China's high-speed rail project. A second project would see trains heading north through Russia to Germany and into the European railway system, and a third line will extend south to connect Vietnam, Thailand, Myanmar and Malaysia. Mr. Wang said that the rail lines will draw together and open up the whole of Central, East and Southeast Asia, which would also allow China to transport valuable raw materials more efficiently. Mr. Wang said the route of the three lines had yet to be decided, but that construction for the South East Asian line had already begun in the southern province of Yunnan and that Burma was about to begin building its link. China has offered to supply money to the Burmese line in exchange for the country's rich reserves of lithium, a metal widely used in batteries. At present, the only rail line that links China to South East Asia is an old track built by the French in Vietnam a century ago. The Asian Development Bank has recently agreed a second PS27 million loan as part of the PS93 reconstruction of Cambodia's network, which should finish by 2013. The cost of the lines from Cambodia to Singapore and then from Vietnam to China could be roughly PS400 million.
Question: According to Wang Mengshu, the three rail lines aim to _ .
Options: (A) be finished in three years (B) match the speed of air travel (C) cover the whole area of Asia and Europe (D) increase efficiency in carrying goods and passengers
Output:
D