This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
In vivo control of citric acid cycle is effected by: 
Select and explain. 
A. Acetyl CoA, B. Coenzyme A, C. ATP, D. Citrate
C: ATP
Answer: C: ATP 
Explanation: C i.e. ATP, E i.e. NADH