Final answer:
The nurse manager is likely expecting the cause for the discrepancy to be unforeseen emergencies and cancellations by patients.
Step-by-step explanation:
The nurse manager is likely expecting the cause for the discrepancy between the assigned visits and the home health nurse's average visits to be d) Unforeseen emergencies and cancellations by patients. Unforeseen emergencies and cancellations by patients can disrupt the nurse's schedule and prevent them from meeting the assigned number of visits.