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
Lee-jones test is used in which poison 
Select and explain. 
A. Phosphorus, B. Cyanide, C. Methyl alcohol, D. Copper
B: Cyanide
Answer: B: Cyanide 
Explanation: Test for cyanide Lee-jones test : Few crystals of ferrous sulphate is added to 5 ml of gastric contents. To it, 5 drops of NAOH is added. The mixture is boiled and cooled. 10 drops of 10% HCL is added to it. Greenish blue color indicates cyanide and purplish color indicate salicylates. Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 473