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: On the morning of November 18, 1755, an earthquake shock Boston. John Winthrop, a professor at Harvard College, felt the quake and awoke. "I rose", Winthrop wrote, "and lighted a candle, looked at my watch, and found it to be 15minutes after four." John Winthrop hurried downstairs to the grandfather clock. It had stopped three minutes before, at 4:12. Except for stopping the clock, the quake had only thrown a key from the mantel to the floor. The clock had stopped because Winthrop had put some long glass tubes he was using for an experiment into the case for safekeeping. The quake had knocked the tubes over and blocked the pendulum .Winthrop, therefore, had the key on the floor. The quake had thrown _ forward in the direction of the quake' s motion by a shock coming from the northwest, perhaps in Canada.
Question: The selection suggests that _ .
Options: (A) earthquakes are common in Boston (B) John Winthrop was a scientist (C) John Winthrop often had difficulty in sleeping (D) Harvard College was a center for earthquake researching
Example Output: B

Example Input: Article: There are many differences between British English and American English.I used to teach a course about the differences between the two.We speak English on both sides of the Atlantic Ocean but we have many differences in our common language.We have examples of the same words having very d ifferent meanings,differing spellings of the same words as well as completely different words for the same things.Here are some examples. A cookie in the US is called a biscuit in the UK.A biscuit in the US is a small cake in the UK.Crisps in the UK,are known as chips,but we British people eat a plate of chips that you call fries in the US.In the UK,a pie can be made from either meat or fruit,while in the US pies are normally made from fruit;pot pies are made from meat.Most things are measured in grams and kilograms in the US,not pounds and ounces. One very obvious difference is the side of the road we each choose to drive on.Petrol in the UK is gas in the US.The place where we fill up our cars,in the UK,is a garage;while in the US,it's a gas station.The term garage is also used as a place to store your car next to or close by your house.In the UK we call a lorry what is known as a truck in the US. An elevator in the US is called a lift here,and the first floor in the US,is calle d the ground floor here,so many visitors get off on the wrong floor in British hotels. I could continue with this. There are countless examples of differences within our one shared language.With so many differences,no wonder it's hard to understand each other well.
Question: The passage is mainly about the differences between British English and American English in _ .
Options: (A) vocabulary (B) grammar (C) sound (D) spelling
Example Output: A

Example Input: Article: studying 20 minutes a day for 20 days. You'll start with the basics and move on to more complex reading comprehension and critical thinking strategies. Please note that although each chapter can be an effective skill builder on its own, it is important that you proceed through this book in order, from Lesson I through Lesson 20. Each lesson builds on skills and ideas discussed in the previous chapters. As you move through this book and your reading skills develop, the passages you read will increase both in length and in complexity. The book begins with a pretest, which will allow you to see how well you can answer various kinds of reading comprehension questions now, as you begin. When you finish the book, take the posttest to see how much you've improved. The text is divided into four sections, each focusing on a different group of related reading and thinking strategies. These strategies will be outlined at the beginning of each section and then reviewed in a special "putting it all together" final lesson. Each lesson provides several exercises that allow you to practice the skills you learn. To ensure you're on the right track, each lesson also provides answers and explanations 'for all of the practice questions. Additionally, you will find practical suggestions in each chapter for how to continue practicing these skills in your daily life. The most important thing you can do to improve your reading skills is to become an active reader. The following guidelines and suggestions outlined will familiarize you with active reading techniques. Use these techniques as much as possible as you work your way through the lessons in this book.
Question: According to the passage, the pretest aims to
Options: (A) tell you where your starting level is (B) arouse your interest in using the book (C) illustrate the structure of the text (D) introduce the test-taking techniques
Example Output:
A