This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Anatomy
For blood and urine, preservative used is 
Select and explain. 
A. Sodium chloride, B. Sodium fluoride, C. Sodium acetate, D. Sodium gluconate
B: Sodium fluoride
Answer: B: Sodium fluoride 
Explanation: For blood, CSF, vitreous humor and urine, sodium fluoride is the preservative (100mg/10ml) Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 404