Final answer:
Supplemental oxygen therapy is the most appropriate treatment for a 60-year-old woman with acute respiratory distress and an oxygen saturation of 84%.
Step-by-step explanation:
The most appropriate treatment for a 60-year-old woman presenting with acute respiratory distress and an oxygen saturation of 84% is b) Supplemental oxygen therapy.
In this case, the patient is experiencing hypoxemia, which means there is a lower-than-normal level of oxygen in her blood. Supplemental oxygen therapy can help increase her oxygen saturation and improve her respiratory distress.