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: Social & Preventive Medicine
[{'content': 'A crowd obeying the orders of the leader is \nSelect and explain. \nA. Mob, B. Herd, C. Band, D. Crowd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]