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: ENT
[{'content': 'Ear pinna develops from ____________ \nSelect and explain. \nA. Ectoderm, B. Endoderm, C. Mesoderm, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans:A.)Ectoderm First branchial cleft is the precursor of external auditory canal. Around the sixth week of embryonic life, a series of six tubercles appear around the first branchial cleft Branchial clefts are ectodermal in origin.', 'role': 'assistant'}]