Final answer:
Elevating the head of the bed to 30-45 degrees best demonstrates understanding of proper oral care for the ventilator-dependent patient to prevent VAP.
Step-by-step explanation:
The action by the graduate nurse that best demonstrates understanding of proper oral care for the ventilator-dependent patient to prevent VAP is c) Elevating the head of the bed to 30-45 degrees. Elevating the head of the bed helps to prevent aspiration of oral secretions and reduces the risk of developing ventilator-associated pneumonia (VAP). Providing oral care every 12 hours, using an antiseptic solution for oral hygiene, and administering prophylactic antibiotics daily are not the most appropriate actions to prevent VAP in this scenario.