Which of the following lists is most representative of "external customers" of a public high school?

The most representative list of "external customers" of a public high school is composed of groups and individuals that utilize or are affected by the school's services but are not part of its internal operations. In this context, external customers typically include entities or individuals that the school serves or interacts with outside of its primary organizational structure.

Students and parents, while intrinsic to the school environment, also interact with external entities such as colleges and potential employers after the students graduate. Colleges represent organizations that may seek to recruit students, assessing their readiness and qualifications for higher education. Potential employers are crucial as they reflect the school's effectiveness in preparing students for the workforce. The town school board acts as an external stakeholder, overseeing and supporting the school's governance. Finally, community volunteer agencies can enhance the educational experience and help students engage with the community, providing additional learning and growth opportunities.

This comprehensive understanding of external customers emphasizes the various stakeholders that play a role in the success and perception of the school's performance and its graduates' readiness for further education or entering the workforce.