A 7-year-old boy is brought to the clinic by his mother with a 2-year history of recurrent pneumonias and difficulty swallowing solid foods. His parents report he often chokes when eating and has chronic cough. Vital signs are stable (HR 98/min, RR 22/min, temperature 37.2°C, SpO2 98% on room air). Physical examination is unremarkable. Chest radiograph shows a right-sided aortic arch. CT angiography demonstrates the aorta arising from the right side of the mediastinum with the esophagus compressed between the aortic arch and the descending aorta. Which embryologic process is responsible for the normal anatomy that failed to occur in this patient?

1. A)Leftward migration and rotation of the truncus arteriosus during weeks 4-6
2. B)Dorsal displacement of the right sixth pharyngeal arch artery (ductus arteriosus)
3. C)Regression of the distal right dorsal aorta between the right seventh cervical and first thoracic arteries
4. D)Rightward rotation of the left fourth pharyngeal arch artery (aortic arch) across the midline to the left side of the esophagusGABARITO
5. E)Ventral translocation of the paired dorsal aortae during pharyngeal arch development