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
All are temporary social groups except 
Select and explain. 
A. Crowd, B. Mob, C. Herd, D. Band
D: Band
Answer: D: Band 
Explanation: 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