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
Lactic acidosis  in  thiamine  deficiency  is  due  to which enzyme dysfunction? 
Select and explain. 
A. Phosphoenol Pyruvate Carboxykinase, B. Pyruvate Dehydrogenase, C. Pyruvate Carboxylase, D. Aldolase
B: Pyruvate Dehydrogenase
Answer: B: Pyruvate Dehydrogenase 
Explanation: In Thiamine deficiency, PDH reaction is defective. So, pyruvate is converted to lactic acid.
Causes of inhibition of PDH leading to lactic acidosis:

Inherited PDH deficiency
Thiamine deficiency
Alcoholics due to thiamine deficiency
Arsenite and Mercury poisoning

Harper 30th edition