A 50-year-old chronic alcoholic presented with complaints of acute confusion, delirium, ataxia and mild memory loss. On ophthalmoscopic examination, ophthalmoplegia was noted along with hypotension. Serum electrolyte levels were normal. Lab findings revealed increased RBC transketolase activity along with reduced blood lactate levels. CT scan of the brain did not reveal any finding, so MRI of brain was planned. Which of the following enzymes uses the above deficient vitamin as a coenzyme: –