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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: 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
Solution: B
Why? 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: Article: When was the last time someone did something unexpectedly nice for you? Not someone you knew, but a total stranger? It's happened to me a few times, but two instances really stand out. A few years ago, I was dining out with a person who kept going on and on about himself, completely unaware of the fact that I was sitting there in misery . It wasn't his company that disappointed me. I was recovering from a bad grade in my study. I could have collapsed in tears right there at the table. When we picked up the check, the waitress said, "Your meal was already paid for." My friend and I didn't have a clue how it happened. Then I remembered a man coming in out of the corner of my eye. He was dressed in mostly white, sat down at the bar, had a glass of wine, stayed for maybe ten minutes and then left. The waitress said, "Yes, the gentleman who was in here a while ago paid for you." Just last year, I was running a half-marathon. With just 0.1 miles to go, I was out of gas. Runners call it "hitting the wall"; I thought I couldn't move another muscle. Out of nowhere, a teenager jogged up next to me and said, "What's your name sweetie? Jennifer? Okay, Jennifer, let's go! Come on! It's just around the corner! You can do it!". And he ran with me until I picked up my pace. I found him at the finish line to thank him for the encouragement only to learn he wasn't even supposed to be in the race that day. He was running in place of someone else. I still shake my head when I think of these momentary angels that came to me at my point of need. Do you have any experiences like this? 
 Question: Why did the author say she was in misery? 
 Options: (A) Because she got into trouble with her friend. (B) Because she couldn't enjoy her meal quietly. (C) Because her friend complained so much. (D) Because she was doing poorly in her study.
Solution:

assistant: D