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': 'Carbon monoxide poisoning is characterized by all except - \nSelect and explain. \nA. Cyanosis, B. Cherry red discoloration, C. Skin blistering, D. Poison with just 10% concentration may be asymptomatic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cyanosis is not a feature of CO poisoning.', 'role': 'assistant'}]