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.
One 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
Solution is here: B
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.

Now, solve this: Article: Americans often plan social gatherings on short notice, so don't be surprised if you get invited to someone's home or to see a movie or baseball game without much warning. If the time is convenient   for you, surely accept their invitation. But if you're busy, don't be afraid to _ the invitation, perhaps suggesting a time that would be better. Your host won't be shamed. Invitations are usually sent in person or over the telephone. The main exception  is for some formal occasions, in which case a written invitation will be mailed. You would normally receive a written invitation to a wedding . For a casual dinner invitation, don't arrive more than 5 minutes early, because your host may still be preparing for your visit. Arriving more than 10 minutes late is considered rude if very few people were invited. If many people were invited, it's OK to arrive a little late, even as much as half an hour late. For example, it's OK to arrive late for a party, for a potluck   dinner or for a social gathering inviting a large group of people. If you're invited for dinner, it's proper to bring the host a bottle of wine, a gift basket of fruit, a box of candy  , or a bouquet of flowers. Don't bring roses, as men often give roses to women on a date  . If you wish to thank the host for his or her hospitality  , it's right to call or send a brief   written thank-you note the next day. 
 Question: The passage is to tell us   _  . 
 Options: (A) how to accept Americans' invitations. (B) something about American social visits. (C) something about American business visits. (D) how to make a living in America.
Solution:
B