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': 'How much is the safely tolerated value of fluoride (mg F/Kg) \nSelect and explain. \nA. 4-Feb, B. 8-Apr, C. 16-Aug, D. 32-64', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Certainly lethal dose (CLD) - 32-64 mg F /Kg body weight\nSafely tolerated dose (STD) - 8-16 mg F / kg body weight (1/4th of CLD)\n\nAlso note these two important values\xa0\n\nProbable toxic dose (PTD)- 2mg F/ Kg body weight\nMinimum toxic dose (MTD)- 5-6 mg F/ Kg body weight.', 'role': 'assistant'}]