Final answer:
The role of the psychiatric nurse in primary prevention can be seen in providing sexual education classes for adolescents.
Step-by-step explanation:
The role of the psychiatric nurse in primary prevention can be seen in option 4: Providing sexual education classes for adolescents. Primary prevention focuses on interventions that prevent the occurrence of mental health issues before they happen. Providing sexual education classes for adolescents falls under primary prevention as it aims to educate and promote healthy behaviors to prevent future mental health issues related to sexual health.