Final answer:
One of the four key regulatory functions of the College of Nurses of Ontario (CNO) is to establish requirements for entry to practice. They are responsible for setting qualifications and standards for nursing licensure.
Step-by-step explanation:
The College of Nurses of Ontario (CNO) has several key regulatory functions to ensure the quality and integrity of nursing practice. Among these, the correct answer to your question - establish requirements for entry to practice - is one of the four key regulatory functions of the CNO. The CNO is responsible for setting the qualifications and standards for nurses to be eligible to practice in Ontario. They do not directly promote the profession, which would be the role of professional associations, nor do they develop nursing education or advocate for changes in institutional policies as those fall outside of their regulatory mandate.