This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Disorders, Subject name: Psychiatry
[{'content': 'What are the EEG waves recorded for parieto occipital region with subject awake an eyes closed: \nSelect and explain. \nA. Alpha waves, B. Beta waves, C. Theta waves, D. Delta waves', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A ref: Physio Ganong, 21 st/e p. 197', 'role': 'assistant'}]