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': 'Common age for otosclerosis is \nSelect and explain. \nA. 5-10 years, B. 10-20 years, C. 20-30 years, D. 30-45 years', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Hearing loss usually stas between 20 to 30 years of age and is rare before 10 and after 40 years. (Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 95)', 'role': 'assistant'}]