The answer is A) description because the teacher is describing the exact consequence for the exact behaviour. We can see that she has little time for nonsense and for misbehaviour and that she is strict and doles out punishments. While we can see this through actual dialogue it is not dialogue that characterizes the teacher. Pacing is used to see how fast or slow the story progresses and reflection is looking back on a story.
I believe the part that says "Digital" is the incorrect part, as of invasive species have nothing to do with computers/electronic devices. Hope this helps! :]