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
A person on fasting for 7 days, the source of energy is: NIMS 11 
Select and explain. 
A. Acetone, B. Acetoacetate, C. Glucose, D. Alanine
A: Acetone
Answer: A: Acetone 
Explanation: Ans. Acetone