Test analysis: The teacher's behavior in this question is an insult to Sanmao, and insult and slander are concrete manifestations of infringing citizens' right to personal dignity, so option C is the correct answer. Violations of personal freedom include: illegal body search, illegal confinement, illegal detention, etc. Violations of the right to life and health include: illegally depriving others of their lives, intentionally or negligently causing injuries to others, etc. , has nothing to do with the infringement in the title, so options a and b should be excluded. The right to education in option D is related to the topic, but judging from the behavior in the materials, the teacher did not infringe on Sanmao's right to education, so it should be excluded.

Comments: This topic is a comprehensive examination of the performance of infringement. Students need to accurately grasp the performance of various rights violations in order to accurately choose the answer. This kind of question is a common question in the legal part of the senior high school entrance examination. Based on relevant current events, the degree of students' mastery of legal knowledge is investigated.