What is the subtlest danger of technology in the story?

Correct answer: It can keep children learning yet make them socially lonely

The governing concept is that technology may preserve functional learning while weakening social connection. Margie is not prevented from studying: the mechanical teacher gives her lessons, tests her, and records marks. The subtler problem is that she learns alone, without classmates, shared activities, or the emotional relationships of a human classroom. Thus efficiency hides a social cost. Option A is correct because it states both parts of the contrast—continued learning and possible loneliness. Option B is false because books remain important and Tommy brings one home. Option C is an extreme claim unsupported by the story. Option D is inaccurate because the mechanical teacher does teach, even though its teaching is limited and impersonal.