阅读下列短文，然后根据短文的内容从每小题的四个选择项中选出最佳的一项。

     “The price of books for our students is just getting higher and higher and, along with the rising cost of tuition (学费). It’s killing these students,” said Peter Jason, a college professor. “Remember, students are one of the poorest groups of people in America. Almost half of them have at least one part-time job. In fact, one of my students has three jobs. And she still manages to have high scores and go to school full-time.”
     Textbook prices are usually high. Adding to that problem, many college teachers change textbooks year after year, their either upgrade to a new edition (版本) or change to a different textbook. This further hurts students because if a teacher no longer uses a textbook, that book has no resale value.
     Dr. Jason decided to make life a little easier and a lot cheaper for his students by writing his own book on public speaking. “Many books have an increased price because of CD-ROMs, lots of color photographs and pictures. I talked to my students, and many of them, like me, prefer to keep things simple. So, a few years ago, I wrote my own textbook. I made sure that it was simple. Compared to most of other public speaking books, mine is half the number of pages, and one-third the price. That is $ 30 instead of $ 90. when I wrote a second edition last year, students only had to buy the 35 new pages. For only $ 7. 00, they had almost a new book.”