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.

Ex Input:
Article: Recent research has claimed that an excess of positive ions in the air can have an ill effect on people's physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is a rough balance between the positive and the negative charged. But sometimes this balance becomes disturbed and a larger proportion of positive ions are found. This happens naturally before thunderstorm, earthquakes when winds are blowing in certain countries. Or it can be caused by a build-up of static electricity indoors from carpets or clothing, or from TV sets, duplicators or computer display screens. When a large number of positive ions are present in the air many people experience unpleasant effects such as headaches, fatigue  , excessive anger, and some particularly sensitive people feel sick or even suffer mental disturbance. Animals are also affected, particularly before earthquakes, snakes have been observed to come out, rats to flee from their burrows, dogs howl and cats jump about unaccountably. This has led the US Geographical Survey to fund a network of volunteers to watch animals in an effort to foresee such disasters before they hit vulnerable areas such as California. Conversely, when large numbers of negative ions are present, then people have a feeling of well-being. Natural conditions that produce these large amounts are near the sea, close to waterfalls or fountains, or in any place where water is sprayed, or forms a spray. This probably accounts for the beneficial effect of a holiday by the sea, or in the mountains with streams or waterfalls. To increase the supply of negative ions indoors, some scientists recommend the use of ionisers. They claim that ionisers not only clean and refresh the air but also improve the health of people sensitive to excess positive ions. Of course, there are the detractors, other scientists, who dismiss such claims and are skeptical about negative/positive ion research. Therefore people can only make up their own minds by observing the effects on themselves, or on others, of a negative rich or poor environment. After all it is debatable whether depending on seismic readings to anticipate earthquakes is more effective than watching the cat. 
 Question: What is an ion according to the passage? 
 Options: (A) It's a charged particle. (B) It's basically static electricity indoors. (C) It's a balance between the positive and negative charged. (D) It's an ill effect on people's physical and psychological health.

Ex Output:
A


Ex Input:
Article: A good memory is a great help in learning a language. Everybody learns his own language by remembering what he hears when he is a small child, and some children, like boys and girls who live abroad with their parents, seem to learn two languages almost as easily as one. In school it is not easy to learn a second language because the pupils have so little time for it, and they are busy with other subjects, too. A man's mind is rather like a camera, but it takes photos not only of what we see but of what we feel, hear, smell and taste. When we take a real photo with a camera, there is much to do before the photo is finished and ready to show to our friends. In the same way there is much work to be done before we can keep a picture forever in our mind. Memory is the diary that we all carry about with us. 
 Question: We usually begin to learn our own language by   _   it. 
 Options: (A) speaking (B) hearing (C) saying (D) teaching

Ex Output:
B


Ex Input:
Article: Tips for Getting the Most out of a "Photo walk" Photo walks are a great way to get out and get clicking, either by yourself, with a couple of friends, or with a group of people. They can be wonderful for seeing a neighborhood or wild space with new eyes, getting inspired to be more creative with angles and subjects, as well as simply spending time with fun people. Here are a few tips for making sure you get the most out of a photo walk. Pick a spot with lots of interest A photo walk is a perfect excuse to go exploring a new area. However, if you've never been to the scene before, you might be disappointed at the final photos. Base your chosen spot on what you feel like photographing---whether that is buildings, people, busy streets, a festival, nature and so on, and make sure the place you're heading for is filled with what you most want to shoot. It will pay off in a satisfying walk if you research your chosen spot beforehand and know what to expect. Invite anyone, no matter what their skill level is You'll be surprised at what you learn from people who seem to know nothing about photography. Even with a simple camera, they can catch some outstanding photos. So bring Aunt Betty or your 10-year-old nephew or anyone else whose company you might enjoy on a walk and keep an open mind. Don't forget them Be sure to take the important small things, such as an extra memory card (or two), an extra fully charged battery, comfortable shoes and clothing. And remember a notepad and pen for taking down notes about places, times, conditions, the names and information of people you meet and any other information you might want to remember about certain shots. Keep an eye out for danger Apart from watching the sky for rain, you'll want to watch out for other people as well. Smartphones are always a target for thieves but they have become much clearer about the value of digital cameras. Don't make yourself a target by standing for a very long time holding your camera out in front of you. If you're in an area that is really busy or you aren't super comfortable, then just be careful about when to use your camera. Imagine your shot in your head before holding up your camera, or use a camera belt wrapped around your wrist or shoulder. 
 Question: To choose a place for a photo walk, you are suggested to   _  . 
 Options: (A) spend time discussing with fun people (B) decide the place on your interest (C) choose famous places (D) find a new area

Ex Output:

B


