This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
[{'content': "True about otosclerosis -a) 50% have family historyb) Males are affected twice than femalesc) More common in Negro's and African'sd) Deafness occurs in 20-30 yrs but less in before 10 yrs and after 40 yrse) Pregnancy has bearing on it \nSelect and explain. \nA. ade, B. bde, C. abd, D. ad", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]