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
[{'content': 'The reaction inhibited in thiamine deficiency is \nSelect and explain. \nA. Pyruvate to acetyl CoA, B. Citrate to alpha ketoglutarate, C. Succinyl CoA to fumarate, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: PDH requires thiamine as a cofactor to convert pyruvate into acetyl CoA.', 'role': 'assistant'}]