This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fatty acid and synthesis, Subject name: Biochemistry
Which of the following is the allosteric activator of Acetyl-CoA carboxylase? 
Select and explain. 
A. Malonyl-CoA, B. Acetyl-CoA, C. Citrate, D. Biotin
C: Citrate
Answer: C: Citrate 
Explanation: Acetyl-CoA carboxylase is active when it is polymerized. Citrate promotes its polymerization. Citrate is an indicator of high-energy status. Palmitoyl-CoA inhibits its polymerization.