Answer:
B) relation
Step-by-step explanation:
In this example, the professor is violating the conversational maxim of relation. In order for a conversation to be interesting, clear and efficient for both the speaker and the listener, it is important that the topics being discussed are all related to each other. Otherwise, the conversation becomes too difficult to follow. In this example, the professor goes on tangents and talks about subjects that are not related to the class. Therefore, he does not follow the rule of relation.