Which side of technology is shown by the machine teacher's instant checking?

Correct answer: Efficiency and speed

The governing concept is the practical efficiency provided by educational technology. The mechanical teacher can examine Margie’s work and display the result immediately, without waiting for a human teacher to collect, mark, and return an exercise. This quick response demonstrates speed, regularity, and automatic processing, so option C is correct. Loneliness is an emotional disadvantage associated with studying alone, not the feature shown by instant checking. Human interaction is reduced rather than increased, and old tradition has no logical connection with an automated assessment process. The example therefore presents a positive functional side of technology even though the story also questions its social and emotional costs.