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
[{'content': 'A person was found dead with bluish green frothy discharge at the angle of mouth and nostrils. What is the diagnosis ? \nSelect and explain. \nA. Arsenic poisoning, B. Copper poisoning, C. Mercury poisoning, D. Lead poisoning', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Blue green (or purple-green) pigmentation of hair, skin, mucosa and perspiration, purple (blue) green line on gums and bluish green frothy discharge from mouth and nostrils is seen in chronic poisoning of copper salt.', 'role': 'assistant'}]