This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Forensic Medicine
[{'content': 'Best method to group an old blood stain is \nSelect and explain. \nA. Benzidine test, B. Spectroscopy, C. Absorption elusion, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Absorption elution method for blood grouping. Others for detecting presence of blood . Ref : Krishnan vij Textbook of Forensic medicine and Toxicology 5th edtion ; pg no - 67', 'role': 'assistant'}]