Which instance exemplifies community service?

Volunteering at a medical tent during a marathon serves as a clear example of community service because it involves offering health-related assistance to individuals participating in the event and the community at large without expectation of monetary compensation. This type of engagement demonstrates commitment to public health and wellbeing, showcases the nurse's professional skills, and promotes community involvement.

The other instances, while beneficial and important to personal or professional development, do not directly represent community service. Working overtime to improve unit workflow focuses more on improving workplace efficiency rather than serving the community directly. Attending a conference for professional development is a personal investment in one's career that primarily benefits the individual rather than the community. Mentoring new nurse graduates involves guiding individuals entering the profession, which contributes to professional development but is a more targeted and individual-centric activity than broader community engagement.