A 4-month-old male infant born at 35 weeks gestation to a mother with poorly controlled gestational diabetes presents with poor feeding, failure to gain weight, and increased work of breathing. The mother reports the infant becomes fatigued during feeds. Vital signs: HR 168/min, RR 52/min, BP 82/58 mmHg, SpO2 99% on room air. Physical examination reveals a hyperdynamic precordium with a palpable thrill at the left infraclavicular region. A continuous 'machinery' murmur is heard throughout systole and diastole. Femoral pulses are bounding. Chest X-ray demonstrates cardiomegaly with pulmonary edema and increased pulmonary vascular markings. Echocardiography confirms left-to-right shunting with a patent ductus arteriosus measuring 4 mm in diameter. Which of the following best explains the clinical presentation in this patient?

1. A)Atrial septal defect with left-to-right shunting
2. B)Ventricular septal defect with Eisenmenger syndrome
3. C)Patent ductus arteriosus with high-flow pulmonary overcirculationGABARITO
4. D)Aortic stenosis with reduced systemic perfusion
5. E)Pulmonary stenosis with right ventricular hypertrophy