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
Example solution: 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.

Problem: Article: We know that many animals do not stay in one place.Birds,fish and other animals move from one place to another at a certain time.They move for different reasons:most of them move to find food more easily,but others move to get away from places that are too crowded. When cold weather comes,many birds move to warmer places to find food.Some fishes give birth in warm water and move to cold water to feed.The most famous migration is probably the migration of fish,which is called "Salmon".This fish is born in fresh water but it travels many miles to salt water.There it spends its life.When it is old,it returns to its birthplace in fresh water.Then it gives birth and dies there.In northern Europe,there is a kind of mouse.They leave their mountain homes when they become too crowded.They move down to the low land.Sometimes they move all the way to the seaside,and many of them are killed when they fall into the sea. Recently,scientists have studied the migration of a kind of lobster .Every year,when the season of bad weather arrives,the lobsters get into a long time and start to walk across the floor of the ocean.Nobody knows why they do this,and nobody knows where they go. So,sometimes we know why humans and animals move from one place to another,but at other times we don't.Maybe living things just like to travel.
Question: Most animals move from one place to another at a certain time to _ .
Options: (A) give birth (B) enjoy warmer water (C) find food more easily (D) find beautiful places
Solution: C