A nurse is caring for an infant diagnosed with tetralogy of Fallot. The infant's caregiver asks the nurse to explain this diagnosis. Which of the following is an accurate statement about this condition?

Rationale: A. Tetralogy of Fallot (TOF) consists of four defects: pulmonary stenosis (narrowing of the pulmonary valve or artery, reducing blood flow to the lungs), ventricular septal defect (VSD, a hole between the ventricles causing mixing of oxygenated and deoxygenated blood), right ventricular hypertrophy (thickening of the right ventricle due to increased workload), and overriding aorta (aorta positioned over the VSD, allowing mixed blood to flow into systemic circulation). This explanation accurately describes the anatomical and physiological features of TOF and helps caregivers understand the condition. B. The mitral valve is located between the left atrium and left ventricle, and its atypical placement is not involved in TOF. TOF affects the right side of the heart and the outflow to the lungs, so attributing the condition to the mitral valve is misleading and incorrect. C. TOF involves four defects, not three. The defects listed in this option (aortic stenosis, atrial septal defect, left ventricular hypertrophy) are unrelated to TOF. Aortic stenosis affects left ventricular outflow, atrial septal defect involves the atria rather than the ventricles, and left ventricular hypertrophy occurs in conditions affecting the left heart, not TOF. This option conflates other congenital heart defects with TOF. D. While TOF does involve mixing of oxygenated and deoxygenated blood, the mixing occurs at the ventricular level due to the VSD, not at the atrial level. Describing the condition as caused by an atrial septal defect misrepresents the anatomy and pathophysiology of TOF. It may lead to misunderstanding about the location and severity of the defect.