Margie's mother's behavior shows which controlled use of technology?

Correct answer: Keeping the machine at the right level for regular study

The governing idea is balanced and controlled use of educational technology. In the story, Margie's mother does not reject the mechanical teacher simply because it is a machine. Instead, when its geography lessons become unsuitable, the County Inspector adjusts it to the correct level so that Margie can continue her regular studies. Thus option A is correct: technology is accepted, but it is monitored and properly configured to serve the learner. Option B is wrong because the machine is not permanently shut down. Option C has no connection with the episode, and option D confuses a telebook with a printed book. The incident shows that technology needs human supervision, diagnosis, and adjustment rather than blind acceptance or total rejection.