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': 'Third window effect is seen in \nSelect and explain. \nA. Perforated tympanum, B. Dehiscent superior semicircular canal, C. Round window, D. Oval window', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Dehiscent superior semicircular canal Dehiscence of bone overlying the superior semicircular canal can cause a constellation of vestibular and auditory symptoms and signs. These abnormalities can be understood in terms of the effect of the dehiscence in creating a third mobile window into the inner ear.', 'role': 'assistant'}]