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: Anatomy
[{'content': 'Middle ear cavity is connected anteriorly to: \nSelect and explain. \nA. Nasal cavity, B. Nasopharynx, C. Mastoid antrum, D. Mastoid air cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: B (Nasopharynx) Ref: Grays Anatomy 40th EdExplanation:Middle ear cavityAnterior wall - Upper canal for tensor tympan muscle & lower canal for auditory tube which communicates to the nasopharynxPosterior wall communicates the mastoid antrum through aditusLateral wall seperates the middle ear from external earMedial wall separates the middle ear from internal ear', 'role': 'assistant'}]