Final answer:
The central idea of 'The Fun They Had' is the challenges of a futuristic school system, describing children's reactions to traditional education.
Step-by-step explanation:
The central idea of the short story The Fun They Had by Isaac Asimov is b) The challenges of a futuristic school system. It revolves around the surprise and nostalgia expressed by two children, Margie and Tommy, who find a real book from the past and compare their individualized, mechanical teaching experiences with the group learning and human teachers of historical schools.
The story serves as a commentary on education, exploring themes of the human element in teaching and the impact of technological advancement on societal structures, such as schools.