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': 'Most commonly used tuning fork in ear examination- \nSelect and explain. \nA. 128 Hz, B. 256 Hz, C. 512 Hz, D. 1024 Hz', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., 512 Hz o Commonly used tuning fork has a frequency of 512 Hz-o Forks of other frequencies, e.g. 256 and 1024 Hz should also be available.", 'role': 'assistant'}]