This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': "All are tuning fork tests except \nSelect and explain. \nA. Schwaback test, B. Grants test, C. Rinne's test, D. Weber's test", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Cold-air caloric test: This test is done when there is perforation of the tympanic membrane because irrigation with water in perforation is contraindicated. The test employs Dundas Grant tube, which is a coiled copper tube wrapped in cloth. The air in the tube is cooled by pouring ethyl chloride and then blown into the ear. It is only a rough qualitative test. Ref: Dhingra 6th Edition pg no 43', 'role': 'assistant'}]