Given the task definition and input, reply with output. 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: When I was at University I studied very hard. But a lot of my friends did very little work. Some did just enough to pass exams. Others didn't do quite enough. Fred Baines was one of them. He spent more time playing than working in the library. Once at the end of the term, we had to take an important test in chemistry. The test had a hundred questions. Beside each question we had to write "True" or "False". While I was studying in my room the night before the test, Fred was watching TV. Fred usually worried a lot the night before a test. But on that night he looked perfectly calm. Thenhe told me of his plan. "It's very simple. There are a hundred questions and I have to get fifty correct to pass the test. I'll just toss the coin to decide the answers. That way, I'm sure I'll get half the questions right." The next day, Fred came happily into the exam room. As he sat tossing a coin for half an hour he marked down his answers. Then he left, half an hour before the rest of us. The next day, he saw the chemistry professor in the corridor. "Oh, good," he said to the teacher, "Have you got the result of the test?" The teacher reached into his pocket and took out a coin. He threw it into the air, caught it in his hand and looked at it. "I'm terribly sorry, Fred," he said, "You failed!"
Question: This story mainly wants to tell us _ .
Options: (A) chemistry is really hard to learn (B) there are many questions for students to prepare. (C) good exam results really need studying hard (D) tossing a coin can not always decide the result
C