Write a multi-choice question for the following article, with the given choices and answer: Article: Dear Editor, I'm now busy in preparing for the Postgraduate Entrance Exam. A few days ago, I happened to see some new guidebooks for those who want to take next year's exam. With too many hopes and without taking it into too much consideration, I bought several that were written by some known for helping candidates for master's degrees. What made me really angry was the starting discovery that the contents of those books were almost exactly the same as some I had bought before. There were only superficial changes in their covers, with more attractive new titles and better designs. The contents were the same. People say that the publishing industry is in a state of chaos these days but I used to be doubtful abut that. I was of the opinion that only people of noble character, prestige , and exceptional talent would produce books for higher education. But these editors are caring little about their readers. I hope that authors and publishing houses will be more responsible for their readers. Don't destroy the image that you have with your readers. Options: A there were a lot of printing mistakes in the books that he had bought B the books were so expensive that he couldn't afford any of them C he found the books he had bought were thin but of poor quality D the books had the same contents as what he had bought before Answer: D the books had the same contents as what he had bought before Question:
The writer was angry because _ .