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
Green blue postmoem discoloration is seen in which poisoning ? 
Select and explain. 
A. Cyanide, B. Carbon monoxide, C. Hydrogen sulphide, D. Hydrogen sulphide
C: Hydrogen sulphide
Answer: C: Hydrogen sulphide 
Explanation: Ans. is 'd' i.e., Hydrogen sulphide