Final answer:
The most likely nursing intervention completed by a case manager in the role of coordinator is arranging, regulating, and balancing the needed health services for the client to ensure timely and effective care.
Step-by-step explanation:
When a case manager is fulfilling the role of coordinator, the nursing intervention that would most likely be completed is d. Arranging, regulating, and balancing needed health services for the client. This entails coordinating schedules and appointments, ensuring that all necessary health services are provided in a timely and efficient manner, and managing any issues that arise during care. The case manager would work to balance the client's care needs with the resources available, facilitate communication among healthcare providers, and help navigate any obstacles to care.