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
Patient with BP 90/60 mmHg, lips and peripheries are cyanosed; blood drawn was chocolate color. Diagnosis is: DNB 10 
Select and explain. 
A. Methemoglobinemia, B. Hypovolumic shock, C. Metal fume fever, D. Alphos poisoning
A: Methemoglobinemia
Answer: A: Methemoglobinemia 
Explanation: Ans. Methemoglobinemia