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: Many of the world's pollution problems have been caused by the crowding of large groups of people into the cities. Supply for the needs of the people leads to further pollution by industry. If the rapid increase of world population in countries continues at the present rate, there may be much greater harm to human beings. Some scientists speak of the increase in numbers of people as "population pollution." About 2,000 years ago, the world population was probably about 250 million. It reached a billion in 1850. By 1930 the population was two billion. It is now three and a half billion. It is expected to double by the year 2,000. If the population continues to grow at the same rate, there will be 25 billion in the world a hundred years from now. Man has been using the earth's resources more and more rapidly over the past years. Some of them are almost used up. Now many people believe that man's greatest problem is how to control the growth of the population. The material supplies in the world will be far from enough to support the human population in time to come, if the present rate of increase continues. Already there is overcrowding in many cities and starvation in some countries. Should man's population keep on growing so rapidly as before? Many people believe that human survival in the future depends on the answer to this question.
Question: The rapid increase in population is considered to be _ .
Options: (A) the increase of resources (B) population pollution (C) the development of mankind (D) the present rate
B

Article: Amazingly, US crime figures have been falling for 20 years now. Of course, the big question is, why? And can any lessons be learnt? One reason could be the fall in the demand for the drug crack. During the 1980s, drug-related crimes soared, mostly caused by desperate crack users. However, according to professor Blumstein, co-author of The Crime Drop in America, news of the dangers of crack use caused its decrease and led to a fall in the number of drug-related crimes. Some say that the adoption of a zero-tolerance policy in many cities has helped lead to a fall in crime. In New York City, for example, mayor Rudy Giuliani imposed strict and automatic punishments for all crimes, including minor offences such as graffiti and littering. Many believe this has had a very strong deterrent effect. Another reason could be smarter policing strategies. Anti-theft measures and educating the community about car theft has helped see a drop in crimes in many areas. Also, the use of crime mapping schemes that can discover identify crime peaks in different parts of the city has helped police target hotspots. Another reason could be that more criminals are now behind bars. Sociologist John Conklin (from Tufts University) says a significant factor behind the fall in crime in the 1990s is the simple fact that many criminals are in jail. In his book Why Crime Rages Fell, he says sentencing was merciful in the 1960s and 1970s, when crime rose. But then more prisons were built and more offenders were imprisoned. Some have linked the fall in violent crime to a decline in children's exposure to lead in petrol. Jessica Wolpaw Reyes says, "Even low to moderate levels of exposure can lead to behavioral problems, reduced IQ, hyperactivity and youth crimes. You can link the decline in lead between 1975 and 1985 to a decline in violent crime 20 years later." Others say that the drop in crime has something to do with birth rates. According to statistics, birth rates peaked between 1957 and 1961, and the proportion of men in the US in their late teens and early 20s (the so-called "criminal age") was highest in the late 70s and early 80s. However, as time went on, the proportion of people in this age group decreased. Others claim that videogames have helped. A recent study has suggested that these games are keeping young people off the streets and therefore away from crime. Advocates of this argue that any effects the games may have in encouraging violent behavior is _ by the fact that the games keep potential criminals indoors and in front of the television. Some argue that the widespread use of camera phones makes some criminals think twice before committing a crime and getting filmed doing it. Also, many believe that the mass use of CCTV has also had an effect. Finally, some say that petty theft just isn't worth it any more. The resale value of second-hand goods such as televisions, cameras or clothes is now so low (or even non-existent) that most people see no point in stealing. So, what do you think?
Question: By writing this article, the writer intends to tell us _ .
Options: (A) the amazing fact that US crime figures are going down (B) the recent statistics showing that crime rates are falling in the US (C) the answers to the question why US crime figures are falling (D) the special policies adopted by the US police that help a drop in crime
C

Article: We live in a culture that sends out very mixed messages about mistakes: We're told we learn by making them, but we work hard to avoid them. So the result is that most of us know that we are going to make mistakes, but deep down, we feel we shouldn't. Experiments with schoolchildren who did well on a given test show that those who were praised for being smart and then offered a more challenging or less challenging task afterward usually chose the easier one. On the other hand, children praised for trying hard-- rather than being smart--far more often selected the more difficult task. If we try hard to avoid mistakes, we aren't open to getting the information we need in order to do better. In a writing study, experiments showed that those who are so scared to make mistakes perform worse in writing tasks than those who aren't as worried about being perfect. They fear receiving any kind of negative feedback, so they don't learn where they went wrong and how to get better. We don't just learn more when we're open to mistakes, we learn deeper. Research tells us that if we're only concerned about getting the right answer, we don't always learn the underlying concepts that help us truly understand whatever we're trying to figure out. Mistakes need to be seen not as a failure to learn, but as a guide to what still needs to be learned. As Thomas Edison said, "I am not discouraged, because every abandoned wrong attempt is another step forward." Furthermore, we often make mistakes because we try new things--we wander away from accepted paths. Teflon, penicillin--these are examples of great discoveries made by mistake. Take a page from Albert Einstein, who said, "Anyone who has never made a mistake has never tried anything new. "
Question: What will happen to students praised for being smart in face of choosing tasks compared to students praised for working hard?
Options: (A) He will ask his teachers for advice. (B) He will hide his mistakes from his teachers. (C) He will work harder to avoid mistakes. (D) He will choose a less challenging task.
D