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
Otosclerosis mostly affects: 
Select and explain. 
A. Malleus, B. Stapes, C. Incus, D. Tympanic membrane
B: Stapes
Answer: B: Stapes 
Explanation: Otosclerosis is caused by immobility of the stapes. Its most distinctive feature is conductive hearing loss, but sensorineural hearing loss and veigo are also common; tinnitus is infrequent. Otosclerosis is suggested by a positive family history, a tendency toward onset at an earlier age, the presence of conductive hearing loss, or bilateral symmetric auditory impairment Treatment with a combination of sodium fluoride, calcium gluconate, and vitamin D may be effective. If not, surgical stapedectomy should be considered.