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
A boy died in an emergency room with white froth in the mouth. The poisoning is due to - 
Select and explain. 
A. Organophosphorus, B. Opium, C. HCN, D. None
B: Opium
Answer: B: Opium 
Explanation: Froth near the mouth or nasal aperture may be due to death by drowning or some poisons like opium or organophosphorus.
Blood mixed frothing from nose and mouth may be due to organophosphorus poisoning.
Death due to drowning or opium poisoning causes fine white copious leathery frothing.