This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lipids, Subject name: Biochemistry
The immediate precursor in the formation of acetoacetate from acetyl-CoA in the liver is: 
Select and explain. 
A. Mevalonate, B. HMG-CoA, C. Acetoacetyl-CoA, D. 3-hydroxyl-butyryl-CoA
B: HMG-CoA
Answer: B: HMG-CoA 
Explanation: Ans. B. HMG-CoA(Ref: Harper 31/e page 210)Hydroxy-3-methylglutaryl-CoA lyase then causes acetyl-CoA to split off from the HMG-CoA, leaving free acetoacetate.