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': 'Slow wave sleep associated with: \nSelect and explain. \nA. Dreams, B. Cardiac arrhythmia, C. Penile intumescence, D. Delta activity', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Delta activity', 'role': 'assistant'}]