This would be stimulus-response conditioning.
There is an experiment called the Pavlov's experiment, in it was proved that repeated exposure to a given stimulus gives a specific behavior being repeated. This is repetition conditioning. An example of this can be that when some one rings a bell, the dog starts salivating. (not exactly our case)
Subliminal conditioning is the conditioning of attitudes by exposure to stimuli that are below the "threshold of conscious awareness." (we can discard this one)
Finally, stimulus-response conditioning is when a previously neutral stimulus (for example, talking about a topic in class) that (with time and conditioning) triggers a conditioned response.
Here is the correct option, first, the teacher remarks several times a topic. With enough time, it will trigger a response on the students when they meet an exercise or something related to that topic.
If you want to learn more about psychology, you can read:
https://brainly.com/question/12011520