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': 'Opening of Eustachian tube in middle ear is in \nSelect and explain. \nA. Medial wall, B. Lateral wall, C. Anterior wall, D. Posterior wall', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Anterior wall has 2 openings, the lower one for eustachian tube and the upper one for the canal of tensor tympani muscle. 2. Opening for Eustachian tube. Reference: Dhingra 6th edition', 'role': 'assistant'}]