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': 'A person on fasting for 7 days, the source of energy is: NIMS 11 \nSelect and explain. \nA. Acetone, B. Acetoacetate, C. Glucose, D. Alanine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Acetone', 'role': 'assistant'}]