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: Trees are useful to man in three important ways: They provide him with wood and other products; they provide him shade;. and they help to prevent droughts and floods. Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important.In his eagerness to make money from trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had. And besides, he is usually too careless to plant and look after new trees. So the forests slowly disappear. This does not only mean that man will have fewer trees. The results are even more serious: for where there are trees, their roots break up soil allowing the rain to sink in and also bind the soil, thus preventing it from being washed away easily;but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When the top-soil is gone, nothing remains but worthless desert. Two thousand years ago,a rich and powerful country cut down its trees to build warships, with which to gain itself an empire .It set up the empire, but, without its trees, its soil became poor and grew weak. When the empire fell to pieces, the home country found itself faced by floods and starvation .
Question: The most important service of trees to man is that _ .
Options: (A) they give them wood and other products (B) they give them shade (C) they help him prevent droughts and floods (D) they help him made money
C

Article: A scientist working at her lab bench and a six-old baby playing with his food might seem to have little in common.After all,the scientist is engaged in serious research to uncover the very nature of the physical world,and the baby is,well, just playing...right?Perhaps,but some developmental psychologists have argued that this"play"is more like a scientific investigation than one might think. Take a closer look at the baby playing at the table.Each time the bowl of rice is pushed over the table edge,it falls in the ground---and, in the process, it belongs out important evidence about how physical objects interact ; bowls of rice do not flood in mid-sit, but require support to remain stable. It is likely that babies are not born knowing the basic fact of the universe; nor are they ever clearly taught it. Instead, babies may form an understanding of object support through repeated experiments and then build on this knowledge to learn even more about how objects interact. Though their ranges and tools differ, the baby's investigation and the scientist's experiment appear to share the same aim(to learn about the natural world ), overall approach (gathering direct evidence from the world), and logic (are my observations what I expected?). Some psychologists suggest that young children learn about more than just the physical world in this way---that they investigate human psychology and the rules of language using similar means. For example, it may only be through repeated experiments, evidence gathering, and finally overturning a theory, that a baby will come to accept the idea that other people can have different views and desires from what he or she has, for example, unlike the child , Mommy actually doesn't like Dove chocolate. Viewing childhood development as a scientific investigation throws on how children learn ,but it also offers an inspiring look at science and scientists. Why do young children and scientists seem to be so much alike? Psychologists have suggested that science as an effort ---the desire to explore, explain, and understand our world---is simply something that comes from our babyhood. Perhaps evolution provided human babies with curiosity and a natural drive to explain their worlds, and adult scientists simply make use of the same drive that served them as children. The same cognitive systems that make young children feel good about feel good about figuring something out may have been adopted by adult scientists. As some psychologists put it, "It is not that children are little scientists but that scientists are big children."
Question: According to some developmental psychologists,
Options: (A) a baby's play is nothing more than a game. (B) scientific research into babies; games is possible (C) the nature of babies' play has been thoroughly investigated (D) a baby's play is somehow similar to a scientist's experiment
D

Article: I love seeing Europeans line up in airports to applaud arriving refugees. But humanitarianism will not guide policy for long. We liberals need to argue from Europe's self-interest: our continent has the need, the space and the ability to accept people. Many European countries are gradually turning into old people's homes. Germany, Italy, Spain and others have some of the lowest birth rates in human history. It is predicted that about one-third of their populations will be aged over 65 in 2050. Germany needs to import at least 350,000 people a year to keep its workforce stable. Suddenly, young ambitious workers are pouring into the country as if called by a genie with a lamp. No wonder Angela Merkel, German Chancellor, has been more welcoming than David Cameron, British Prime Minister. But all over Europe, carers for old people are already in need. Norway found oil under the seabed but it would have been better off if it had discovered 50,000 nurses there instead. Many rightwingers think we have reached our limits. This feeling is widespread. And it's true that Western Europe is one of the most densely populated regions on earth. Indeed, density has long been Europe's unique selling point: with so many people of different nations closely packed together, we have always traded goods and exchanged ideas fast. That's why the scientific revolution of the 16th and 17th centuries happened here. But we have plenty more room. Many European cities aren't dense enough. Now east Germany, north-western Spain and gorgeous mountain villages in Italy are losing people. Lots of cities have unused industrial land. Humans inhabit a slice of the EU's territory. Only about 2.5 per cent of the EU's land is used for housing, estimates the European Commission. By contrast, a whopping 43 per cent was used for agriculture in 2009, it says. That's too much. We could turn more land into forest or into green landscapes where people can relax and play. Making that transition is feasible because we now use agricultural land inefficiently. Migrants often spend years locked up together in serious government-funded "migrant centers". However, the way to learn a new country's language, make friends and find work is to live with a local. This crisis has shown that lots of Europeans are willing to take refugees into their homes. After Iceland's government said it could take only 50 Syrian refugees, many Icelanders came forward offering to take a far greater number into their own homes. People aren't just sitting around waiting for government to do something. We need migrants, and we can accommodate them. If opponents just don't like foreigners, they should say so instead of pretending to be hardheaded pragmatists .
Question: Why is Angela Merkel willing to take in refugees according to the passage?
Options: (A) Germany has already stepped into aged society. (B) Birth rates in Germany are the lowest in history. (C) She is kind and shows sympathy for homeless people. (D) Refugees can make up the shortage of labor in Germany.
D