Final answer:
The nurse can delegate repositioning the patient every 2 hours to nursing assistive personnel to prevent pressure ulcers in an older adult patient.
Step-by-step explanation:
The action that the nurse can delegate to nursing assistive personnel (NAP) to help prevent the development of pressure ulcers in an older adult patient is to reposition the patient at least every 2 hours. Repositioning the patient regularly helps to relieve pressure on specific areas and improves blood flow, reducing the risk of pressure ulcers. Other actions mentioned in the options, such as assessing bony prominences, educating the family, and assisting with food selection, are important aspects of care but may require the expertise of the nurse.