London has a new magazine. But it's not printed on paper. Everyone who has a television can receive it because it is on TV. In order to read this magazine you have to have a _ . Each page of it is numbered, so you only have to dial the number to choose which subject you want to read about. There's a wide choice--- everything is included from cooking to the latest sports news. If you want to read the news, the first thing you have to do is to turn to the index page which has an easy-to-remember page number, 100 for example. Then you start choosing what you want to read. The news is on pages 101 to 109, so you push out the numbers and the news appears written across your screen. Perhaps you want to go out in the afternoon, so you press 181, and a brightly colored weather map appears on the screen. But the weather is terrible so you decide to go shopping and dial 162 for a list of the week's best bargains. But should you drive or take the train ? To answer the question you only have to press 189 for the traffic report. It's very simple to use. But probably the best thing about the service is that it's being updated all the time. Journalists type new material directly onto the screen and whole pages of the magazine can be replaced in minutes. London has already had three services. One, transmitted by ITV, is called ORACLE, while the other two, on BBC, are called CEEFAX, because they let you see facts. Although CEEFAX and ORACLE have been operating for some time, they have not been well publicized. BBC engineers do not think that their idea will ever replace books and newspapers because they can be taken with you everywhere. But many people agree that this is a breakthrough as great as the invention of printing, which could change not just our reading habits but our whole way of life. The passage is mainly about  _  .
a new magazine printed in London a popular TV program with three services a great breakthrough in printing an up-to-date way of keeping up to date
Question: London has a new magazine. But it's not printed on paper. Everyone who has a television can receive it because it is on TV. In order to read this magazine you have to have a _ . Each page of it is numbered, so you only have to dial the number to choose which subject you want to read about. There's a wide choice--- everything is included from cooking to the latest sports news. If you want to read the news, the first thing you have to do is to turn to the index page which has an easy-to-remember page number, 100 for example. Then you start choosing what you want to read. The news is on pages 101 to 109, so you push out the numbers and the news appears written across your screen. Perhaps you want to go out in the afternoon, so you press 181, and a brightly colored weather map appears on the screen. But the weather is terrible so you decide to go shopping and dial 162 for a list of the week's best bargains. But should you drive or take the train ? To answer the question you only have to press 189 for the traffic report. It's very simple to use. But probably the best thing about the service is that it's being updated all the time. Journalists type new material directly onto the screen and whole pages of the magazine can be replaced in minutes. London has already had three services. One, transmitted by ITV, is called ORACLE, while the other two, on BBC, are called CEEFAX, because they let you see facts. Although CEEFAX and ORACLE have been operating for some time, they have not been well publicized. BBC engineers do not think that their idea will ever replace books and newspapers because they can be taken with you everywhere. But many people agree that this is a breakthrough as great as the invention of printing, which could change not just our reading habits but our whole way of life. The passage is mainly about  _  .
A. a new magazine printed in London
B. a popular TV program with three services
C. a great breakthrough in printing
D. an up-to-date way of keeping up to date
Answer: