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
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 
Select and explain. 
A. ade, B. bde, C. abd, D. ad
A: ade
Answer: A: ade 
Explanation: None