Which of the following may not be defined as a public officer?

A volunteer firefighter may not be classified as a public officer in the same way that the other options are. Public officers typically hold a defined position within government institutions and receive formal authority to act on behalf of the public. Deputy sheriffs, police chiefs, and city attorneys are all paid employees who carry out specific duties under governmental statutes, representing local or state authorities.

In contrast, volunteer firefighters often serve without compensation and may not have the same level of formal authority or definition as a public officer. Their role, while critical to the community and often supported by the municipal government, does not necessarily confer the same responsibilities or public officer status recognized in formal legal terms, as their position might be more similar to that of community service rather than a government employee.