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 input: 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
Example output: B
Example explanation: 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.
Q: Article: prefix = st1 /Britainis facing a sharp rise in its rat population as growing numbers of people leave fast food scraps in the street , an environment group warned . Keep Britain Tidy said the rodents were stopping their traditional hunts underground and were roaming the streets ,tempted by discarded burgers ,pizzas and crisps. "The rat population is on the rise and soon it'll be as common to see a rodent on our street as it is to see a dog or a cat," said group Director ,Sue Nelson. The practice of dumping fast food litter and scraps on the street rather than in the trash-with young men the worst offenders-was behind the rise. According to the National Rodent Survey in 2005, Britain's rat population has grown by nearly one quarter since 2000 and is now estimated at 60 million , two million more than the human population. On average a rat can give birth every 24--28 days and just a single pair of rats can produce a colony of 2,000 a year. Around 200 people a year get Weil's Disease----an infection which can lead to liver or kidney failure and eventually death and which is arrived in rat's waste. To highlight the issue , Keep Britain Tidy launched a cinema ad entitled "How close do you want them to get?" The advertisement gave a shocking image of a young woman sleeping in a bed of rots, echoing the nightmare scene from James Herbert's classic horror tale The Rats, in which mutant rodents begin to prey on humans.
Question: Where did the rodents use to search for food?
Options: (A) In the Street . (B) Under the ground. (C) From the trash cans. (D) In burger shops.
A:
B