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 normal adult human electroencephalogram (EEG)a) Will not show high frequency waves during stage 3 sleepb) Shows alpha rhythm when a person is awake but inattentivec) Has lower frequency waves during mental activityd) Is predominated by large amplitude waves during REM sleep \nSelect and explain. \nA. ac, B. a, C. ab, D. bc', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Stages of sleep and rhythm\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Beta rhythm- Alert, awake, maximum concentration. (High frequency, low voltage)\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Alpha rhythm- Eyes closed, mind wandering, less attentiveness\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Theta rhythm- Stage 1 NREM\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Sleep spindles, K complex- Stage 2 NREM\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Delta rhythm- Deep sleep (Stage 3 & 4 NREM), Rhythm is slow.\n\xa0\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Beta Rhythm and occasional alpha rhythm- REM (Rapid, low voltage rhythm)', 'role': 'assistant'}]