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 - 
Select and explain. 
A. beta-hydroxy-methyl glutaryl COA - Mevalonic acid, B. Acetyl COA+CO2 + AIP - Matonyl COA+ADP+Pi, C. L-Methyl malonyl COA Succinyl COA, D. Lactose + H2O - Glucose + Galactose
A: beta-hydroxy-methyl glutaryl COA - Mevalonic acid
Answer: A: beta-hydroxy-methyl glutaryl COA - Mevalonic acid 
Explanation: Ans. is 'a' i.e., b-hydroxy-b-methyl glutary1 COA- Mevakmic acid o HMG-CoA reductase is the rate limiting enzyme in cholesterol synthesis.