Final answer:
The College of Nurses of Ontario's overarching mandate is to protect the public interest. This is achieved through practicing standards, disciplinary procedures, and entry to practice requirements.
Step-by-step explanation:
The College of Nurses of Ontario (CNO) has several key mandates, which include protection of the public interest, the development of practice standards, providing a disciplinary body, and creating entry to practice requirements for nurses in Ontario. Specifically, the mandate of CNO is to regulate nursing to protect the public's right to quality nursing services by providing leadership to the nursing profession in self-regulation. It is empowered by legislation to establish, maintain, and enforce standards for entry into practice, and it ensures ongoing competence by its registrants.
Though all the options listed contribute to the CNO's overarching mandate, the most encompassing answer is b. to protect the public interest, as all other functions ultimately aim towards this goal.