This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Main pa of pulmonary aery is a derivative of which of the following branchial arch? \nSelect and explain. \nA. 2nd arch, B. 3rd arch, C. 4th arch, D. 6th arch', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The ventral pa of the 6th arch forms the main pa of the pulmonary aery. The dorsal pa on the left side persist as ductus aeriosus which closes after bih and remains as ligamentum aeriosum. The dorsal pa on the right side disappears. Vascular elements of branchial arches:First arch: Maxillary aerySecond arch: Stapedial aeryThird arch: Common carotid and internal carotid aeryFouh arch: On the right side it forms the first pa of subclan aery and on the left side it forms the main pa of arch of aoaRef: Bedside Clinics In Surgery By M.L. Saha page 363.', 'role': 'assistant'}]