Margie's thought that children must have had fun in old times points to what?

Correct answer: Learning with human teachers and classmates can be joyful

The governing concept is contrast between isolated, machine-based schooling and shared human schooling. Margie studies alone at home, follows the mechanical teacher's programmed lessons, and finds the experience dull. After Tommy explains that children once went to a school building, learned together, and were taught by people, she imagines that such children must have enjoyed themselves. Her thought does not mean that machines at home are always entertaining, nor does it claim that geography or reading is impossible or wrong. Option A is correct because it captures the story's suggestion that companionship, conversation, and a human teacher can make learning lively and joyful.