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': 'When does marbling occur after death of a person? \nSelect and explain. \nA. After 36 hours, B. Within 36 years, C. After 7 days, D. Within 2 hours', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Marbling is due to conversion of haemoglobin into sulphmethemoglobin in blood vessels. It occurs around 36-48 hours after death.', 'role': 'assistant'}]