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: Physiology
[{'content': 'The frequency of beta waves (per sec) in EEG is \nSelect and explain. \nA. 0-4, B. 7-Apr, C. 13-Jul, D. 13-30', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. 13-30', 'role': 'assistant'}]