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': 'Normal hearing: \nSelect and explain. \nA. 20-20,000 hz, B. 30 - 30,000 hz, C. 200-2000 hz, D. 300 - 3000 hz', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) 20 - 20,000lizRef: Dhingrays ENT 6th ed./14-15* Normal hearing capacity is from 20 Hz to 20,000 Hz.* Function of hearing is by cochlea, which has 2 ends broadly. Apex and Base. Apex is for low frequency sound (20 Hz) and Base is for high frequency sound (20,000 Hz).', 'role': 'assistant'}]