This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Physiology, Subject name: Physiology
[{'content': 'The EEG rhythm having lowest frequency is- \nSelect and explain. \nA. Alpha, B. Beta, C. Delta, D. Theta', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. DeltaThe various types of EEG waveforms are depicted below-', 'role': 'assistant'}]