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: Many people say dolphins are very intelligent. They seem to be able think, understand, and learn things quickly. But they are smart like humans or more like cats or dogs? Dolphins use their brains differently from people. But scientists say dolphin intelligence and human intelligence are alike in some ways. How? FACT 1: Talk to Me Like humans, every dolphin has its own "name". The name is a special whistle . Each dolphin chooses a specific whistle for itself, usually by its first birthday. Actually, scientists think dolphins, like people, "talk" to each other about a lot of things, such as their age, their feelings, or finding food. And, like humans dolphins use a system of sounds and body language to communicate. But understanding their conversations is not easy for humans. No one "speaks dolphin" yet, but some scientists are trying to learn. FACT 2: Let's Play Dolphins are also social animals. They live in groups called pods, and they often join others from different pods to play games and have fun ---just like people. In fact, playing together is something only intelligent animals do. FACT 3: Fishermen's Helpers Dolphins and humans are similar in another way: both make plans to get something they want. In the sea of southern Brazil, for example, dolphins use a interesting strategy to get food. When fish are near a boat, dolphins signal to the fishermen to put their nets in the water. Using this method, the men can catch a lot of fish. What is the advantage for the dolphins? Why do they assist the men? The dolphins get to eat some of the fish.
Question: What is the text mainly about?
Options: (A) The comparison between dolphins and humans. (B) The relationship between dolphins and humans. (C) Different types of dolphins. (D) The habitual behavior of dolphins.
Example Output: A

Example Input: Article: Oyster What is an Oyster card? Oyster is the easiest way to pay for journeys on the bus, Tube, tram, Docklands Light Railway (DLR), London Overground and National Rail journeys in London. You can store your travel cards, Bus&Tram Pass, season tickets and credit to pay for journeys as you go. Where to get an Oyster card? There are a number of ways for you to get an Oyster card: * At over 3,900 Oyster Ticket stops * At Tube and London Overground station ticket offices * At some National Rail stations * At London Travel information Centres * Online at tfl. gov. uk/oyster How to use an Oyster card? To pay the correct fare on the Tube, DLR, London Overground and National Rail services, you must always touch in on the yellow Oyster card reader at the start of your journey, and touch out at the end. If you don't, a maximum cash Oyster fare will be changed. When using the bus or tram, you must only touch in at the start, but not at the end of your journey. What happens if I don't visit London very often? Don't worry. Any pay as you go credit on your card will not expire , so you can keep it for your next visit or lend it to a friend. Fares Traveling by Tube from Central London (Zone l)to Heathrow (Zone 6) Adult Oyster single fare PS 4. 20 Monday to Friday 06:30 - 09:30 and 16:00 -19:00 PS 2. 70 at all other times including public holidays Adult single cash fare PS 5.00 For further information, visit tfl.gov. uk /fares.
Question: Which of the following is TRUE about Oyster cards?
Options: (A) They are limited in use to the owners themselves. (B) On National Rail services you must touch them on the reader twice. (C) They are not suitable for those who don't visit London often. (D) Oyster card Tube fares cost more on public holidays than on weekdays.
Example Output: B

Example Input: Article: The most complex object known to humanity is the human brain -- and not only is it complex, but it is one of the few natural phenomena that science has no consciousness of. To try to replicate something that is so poorly understood may therefore seem like pride. But you have to start somewhere, and International Business Machines (IBM) and the Ecole Polytechnique Federale de Lausanne (EPFL), in Switzerland, propose to start by replicating "in silico", one of the brain's building blocks. In a partnership announced, the two organizations said they would be working together to build a simulation of a structure known as a neo-cortical column on a type of IBM supercomputer that is currently used to study the molecular functioning of genes. If that works, they plan to use more powerful computers to link such simulated columns together into something that mimics a brain. In a real brain, a neo-cortical column is a cylindrical element about a third of a millimeter in diameter and three millimeters long. It is these columns, arranged side by side like the cells of a honeycomb, which make up the famous "grey matter" that has become shorthand for human intelligence. The Blue Gene/L supercomputer that will be used for the simulation consists of enough independent processors for each to be programmed to mimic an individual nerve cell in a column. The EPFL's contribution to the Blue Brain Project will be to create a digital description of how the columns behave. The database from its Brain Mind Institute will provide the raw material for the simulation. Biologists and computer scientists will then connect the artificial nerve cells up in a way that mimics nature. They will do so by assigning electrical properties to them, and telling them how to communicate with each other and how they should modify their connections with one another depending on their activity. That will be no mean feat. Even a single nerve cell is complicated, not least because each one has about 10,000 connections with others. And nerve cells come in great variety--relying, for example, on different chemical transmitters to carry messages across those connections. Eventually, however, a digital representation of an entire column Should occur. Assuming that the growth of computing power continues to follow Moore's Law, the leader of IBM's side thinks it should be practical to mimic an entire human brain in silico this way in ten to fifteen years. Such an artificial brain would, of course, be a powerful research tool. It would allow neurological experiments that currently take days in a "web lab" to be conducted in seconds. The researchers hope that their simulated brain will reveal the secrets of how certain psychiatric and neurological, disorders develop. But that is probably not the real reason for doing it. The most interesting question, surely, is whether such an artificial brain will be intelligent, or conscious, or both.
Question: In a real brain, a neo-cortical column _ .
Options: (A) looks like the cells of a honeycomb (B) is a simulation of a structure (C) is the famous "grey matter" (D) contains a large number of nerve cells
Example Output:
D