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
The lethal dose of fluoride for 70 kg adult is: 
Select and explain. 
A. 32-64 mg of fluoride/kg body weight, B. 50-60 mg of fluoride/kg body weight, C. 30-70 mg of fluoride/kg body weight, D. 60-80 mg of fluoride/kg body weight
A: 32-64 mg of fluoride/kg body weight
Answer: A: 32-64 mg of fluoride/kg body weight 
Explanation: CERTAINLY LETHAL DOSE (CLD) : 32 - 64 mg of fluoride/kg body wt.
SAFELY TOLERATED DOSE (STD) : 8 - 16 mg of fluoride/kg body wt.
Ref: Soben peter 5th edition pg no:280