Telebooks being normal and printed books seeming strange show which change?

Correct answer: Reading culture had become screen-centred

The governing concept is the change in the medium through which people commonly read and learn. Tommy and Margie are accustomed to telebooks, so a paper book from the past looks strange to them. This does not mean that children have stopped reading; rather, reading has shifted from printed pages to electronic screens. Option C is correct because it describes a screen-centred reading culture. Option A is too extreme, since the children still read regularly. Option B is unrelated, as the story actually presents mechanical teachers instead of returning human teachers. Option D reverses the contrast: the old schools used printed books and human teachers, while the future setting relies on advanced technology. The detail also shows how familiar technology can make an older, once-normal practice appear unusual.