After diagnosis and initial treatment of a pre-school age child with cystic fibrosis, the nurse provides home care instructions to the parents. Which statement by the child's parents indicates that understanding of the home care treatment to promote pulmonary function?

Rationale: A. "Chest physiotherapy should be performed twice a day before a meal.” Chest physiotherapy helps clear mucus from the lungs and is most effective when done before meals to prevent vomiting and optimize lung function and oxygenation. B. "Administer a cough suppressant every 8 hours." Cough suppressants are generally avoided in cystic fibrosis because coughing is necessary to mobilize and expel thick secretions from the airways. C. "Energy should be conserved by scheduling minimally strenuous activities." Physical activity is encouraged to enhance lung expansion and mucus clearance. Energy conservation is not the priority unless the child is acutely ill. D. "Maintain supplemental oxygen at 4 to 6 L/minute." High-flow oxygen is not routinely used and may suppress respiratory drive. Oxygen is used with caution and only as prescribed in advanced disease or during exacerbations.