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
Pyruvate dehydrogenase is inhibited allosterically by ? 
Select and explain. 
A. AMP, B. Pyruvate, C. NADH, D. `Insulin
C: NADH
Answer: C: NADH 
Explanation: Ans. is 'c' i.e., NADH