This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cholesterol and Lipoproteins, Subject name: Biochemistry
Rate limiting step in cholesterol synthesis is? 
Select and explain. 
A. HMG CoA synthetase, B. HMG CoA reductase, C. Thiokinase, D. Mevalonate kinase
B: HMG CoA reductase
Answer: B: HMG CoA reductase 
Explanation: Ans. (b) HMG CoA reductaseRef Harper Biochemistry 29/e, / 251, 254