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
Thiamine deficiency decreases cellular metabolism because: 
Select and explain. 
A. Thiamine is a coenzyme for pyruvate dehydrogenase and alfa-ketoglutarate dehydrogenases, B. Activity of transketolase is inhibited, C. It is required for the process of transamination, D. It is a cofactor in oxidative reduction
A: Thiamine is a coenzyme for pyruvate dehydrogenase and alfa-ketoglutarate dehydrogenases
Answer: A: Thiamine is a coenzyme for pyruvate dehydrogenase and alfa-ketoglutarate dehydrogenases 
Explanation: Thiamine deficiency results in decreased energy production because TPP interferes with its coenzyme for pyruvate and alphaketoglutarate dehydrogenase.Chronic peripheral Neuritis, Beriberi & Wemicke Encephalopathy with Korsakoff's Psychosis.Thiamin requirements increase in excess intake of carbohydrates and its deficiency leads to decreased energy production