This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': 'The following structure represents all the 3 components of the embryonic disc \nSelect and explain. \nA. Tympanic membrane, B. Retina, C. Meninges, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The outer epithelial layer formed by the ectoderm, inner mucosal layer by the endoderm and middle fibrous layer by the mesoderm. Ref: Dhingra 6th edition page no.12', 'role': 'assistant'}]