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: Forensic Medicine
Fatal dose of Pottasium cyanide is: 
Select and explain. 
A. 5 mg, B. 10 mg C, C. 20 mg D., D. 200 mg
D: 200 mg
Answer: D: 200 mg 
Explanation: 200 mg