Final answer:
The most professional response for Sue is to speak directly with the staff nurse to address the absenteeism and rumored resignation, thereby upholding professionalism and workplace ethics.
Step-by-step explanation:
Sue, a nurse manager, has several options regarding a staff nurse who has been frequently absent and may be planning to resign. Among her options, the most professional approach would be to speak directly with the staff nurse to discuss the situation. This action respects the staff nurse's privacy and the opportunity for an open conversation offers clarity. It's crucial to handle such situations delicately to maintain professionalism and workplace ethics. Immediate termination or soliciting more information from the whistleblower might create legal or ethical issues. Additionally, doing nothing is not advisable as it does not address the absenteeism or potential resignation.