This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Social science, Mental health & Genetics, Subject name: Social & Preventive Medicine
[{'content': 'All are temporary social groups except \nSelect and explain. \nA. Crowd, B. Mob, C. Herd, D. Band', 'role': 'user'}, {'content': "Answer: D \nExplanation: Crowd,mob and herd are temporary social groups.Band is a permanent social group. Ref:p.738 25th edition Park's Textbook of Preventive and Social Medicine", 'role': 'assistant'}]