Printed books becoming rare shows which cultural result of technology?

Correct answer: Movement of knowledge from physical to digital form

The correct answer is D. In the story, Margie and Tommy normally read telebooks, so a printed book from the past seems unusual and valuable. This detail represents a cultural shift in the form through which knowledge is stored and accessed: information has moved from paper volumes to electronic or digital texts. Option A is wrong because the children still read; only the medium has changed. Option B is the opposite of the story, since mechanical teachers have replaced regular human teachers. Option C is unsupported because education takes place at home rather than in expanding school buildings. The rare printed book therefore symbolizes technological change in reading habits and the material form of knowledge.