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': 'Not a test for Eustachian tube patency ? \nSelect and explain. \nA. Tympanometry, B. Toynbee, C. Valsalva, D. Frenzel maneuver', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Tympanometry Tests for Eustachian tubepatency Valsalva test Methylene blue test Sonotubometry Politzer test Toynbee test Frenzel maneuver Catheterization Inflation - Deflation test", 'role': 'assistant'}]