Answer:
The students are robots programmed to be perfect.
Explanation:
Robots do exist in the world, but not to the concept of the creation of an AI that can function like a normal human being. So when it comes to self-vacuum cleaners, they're programmed to do their work efficiently, eliminating option 3. And schools already follow a schedule. Yet, to program and create a robot/android to be and act like a normal human is beyond the reality of our scientific progression in today's world. This would suggest that the story is science fiction, instead of a follow-on reality.