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
Which of the following is most effective for gluconeogenesis: 
Select and explain. 
A. Fructose 2,6 bisphosphate inhibits fructose 1,6 Bisphosphatase, B. Acetyl CoA activates Pyruvate carboxylase, C. Acetyl CoA inhibits Pyruvate carboxylase, D. Citrate activates Acetyl CoA carboxylase
B: Acetyl CoA activates Pyruvate carboxylase
Answer: B: Acetyl CoA activates Pyruvate carboxylase 
Explanation: Acetyl CoA can never be conveed to glucose but acetyl CoA activates the first step of gluconeogenesis (pyruvate carboxylase). When OAA is used for gluconeogenesis in fasting state, then acetyl CoA is not used up in TCA. So acetyl CoA accumulates. acetyl CoA - allosteric activator of pyruvate carboxylase. This reaction is anaplerotic reaction (replenish TCA intermediate OAA). Option 4- Activation of Acetyl CoA carboxylase by Citrate leads to increased fatty acid synthesis and not gluconeogenesis. Option 1- Fructose 2,6 bisphosphate inhibits fructose 1,6 Bisphosphatase (an enzyme of gluconeogenesis) hence decrease gluconeogenesis.