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': 'What is true in case of perforation of pars flaccida - \nSelect and explain. \nA. CSOM is a rare cause, B. Associated with cholesteatoma, C. Usually due to trauma, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tympanic membrane can be divided in 2 parts:\nParstensa : It forms most of the tympanic membrane. Its periphery is thickened to form fibro cartilaginous ring called as\xa0annulus tympanicus.\nPars Falccida : It is situated above the lateral process of malleus between the notch of Rivinus and the anterior and posterior\xa0malleolar fold.\nRef. Dhingra 6/e p59, 5/e p 78', 'role': 'assistant'}]