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': 'Patient with BP 90/60 mmHg, lips and peripheries are cyanosed; blood drawn was chocolate color. Diagnosis is: DNB 10 \nSelect and explain. \nA. Methemoglobinemia, B. Hypovolumic shock, C. Metal fume fever, D. Alphos poisoning', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Methemoglobinemia', 'role': 'assistant'}]