The potential of closed-circuit television and other electronic teaching tools is so great

that it is inspiring to imagine "the school of tomorrow". Televised lesson will be given in a central building having perhaps four or five master studios. The lesson will be carried out into classrooms all over a city, or even an entire country. After a televised lesson has been given, the classroom teacher will take over for the all-important "follow-up" period. The students will ask any troublesome questions, and difficult points will be cleared up through discussion. The teacher in the classroom will have additional electronic tools. On the teachers desk, the traditional bright red apple will have been replaced by a multiple-control panel (控制板) and magnetic tape players. The tape machines will run prerecorded lessons which pupils will follow by headphones. The lesson will be specifically connected closely to the students levels of ability. For instance, while the class as a whole studies history, each student will receive an individual history lesson directed to his particular level of ability. Should questions arise, the students will be able to talk directly to the teacher on individual "intercoms" (对讲装置) without disturbing the rest of the class. In this way, the teacher will be able to conduct as many as three classes at the same time.

The closed-circuit television will probably carry lessons to______.

A．only a single classroom in the school

B．all the schools with classrooms

C．all the classrooms in the world

D．all the classrooms in a city or a country