This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gluconeogenesis, Subject name: Biochemistry
Pyruvate is converted to which substance to start gluconeogenesis? 
Select and explain. 
A. Oxaloacetate, B. Phosphenol pyruvate, C. Cis-aconitate, D. Succinate
A: Oxaloacetate
Answer: A: Oxaloacetate 
Explanation: Ans. (a) OxaloacetateRef Harper's Biochemistry 28/e, chapter 20