The difference between telebook and printed book shows not only medium but also what?

Change in educational culture and time

The governing concept is that an object can symbolize a change in culture and historical time, not merely a change in physical form. The telebook belongs to Margie's futuristic world, where information is delivered through screens and education occurs through home machines. The printed book, discovered by Tommy, belongs to an earlier educational culture in which children used tangible books and attended shared schools. Their contrast therefore helps the reader compare two ways of learning and two periods of society. Option B is correct. Options A, C, and D refer to food, sport, and clothing, none of which is developed through the book comparison. The contrast also makes Margie reconsider what education may once have felt like.

This is a Class 9 English question. Chapter: The Fun They Had. Topic: Education.