Final answer:
The correct nursing intervention for a postoperative patient who has vomited yellow-green liquid and reports nausea would be to apply a cool washcloth to the forehead and provide mouth care.
Step-by-step explanation:
The question relates to appropriate nursing interventions for a postoperative patient experiencing nausea and vomiting. Offering herbal supplements is not generally a first-line nursing intervention, and walking might not be suitable immediately after vomiting. Based on standard nursing practices, applying a cool washcloth to the patient's forehead and providing mouth care can help soothe the patient and manage symptoms non-pharmacologically. Discontinuing medications without a doctor's directive is not within standard nursing practice and could be harmful if the medications are essential for the patient's treatment. Therefore, the correct response would be b. Apply a cool washcloth to the forehead and provide mouth care.