This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Forensic Toxicology - Concepts, Statutes, Evidence, and Techniques, Subject name: Forensic Medicine
Fatal dose of potassium cyanide is? 
Select and explain. 
A. 5 mg, B. 10 mg, C. 20 mg, D. 200 mg
D: 200 mg
Answer: D: 200 mg 
Explanation: ANSWER: (D) 200 mgREF: Textbook Of Forensic Medicine and Toxicology: Principles and Practice by Vij page 695Fatal dose of cyanide:HCN gas - 100-200 ppm in airHCN liquid- 50-60 mgKCN, NaCN- 150-300 mg (200 mg as per Parikh)