Final answer:
The most appropriate oxygen delivery device to use when transporting a patient on low-concentration oxygen and not in acute respiratory distress is the Nasal cannula.
Step-by-step explanation:
When transporting a patient who is on physician prescribed low-concentration oxygen and is NOT in acute respiratory distress, the most appropriate oxygen delivery device to use is the Nasal cannula. The nasal cannula is a simple and comfortable device that delivers oxygen through two small prongs that fit into the patient's nostrils. It is commonly used for patients who require low levels of supplemental oxygen and are not in immediate need of respiratory support.