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: Dental
[{'content': '"NALGONDA" technique of defluoridation was developed at: \nSelect and explain. \nA. Chennai, B. Nagpur, C. Nalgonda, D. Bangalore', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]