The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 42-year-old chronic alcoholic man was admitted to the hospital for inappropriate behavior and disturbed memory. He presents with severe retrograde memory loss, confusion, and confabulation. Neurologic examination showed horizontal nystagmus. He also has bilateral pretibial pitting edema and perioral erythema. CT studies of the brain were normal. The duty physician suspects the patient may be vitamin deficient. Which of the following reactions does the deficient vitamin mediate?   (A) Alpha-Ketoglutarate + NAD+ + CoA <=> Succinyl-CoA + CO2 + NADH   (B) Succinate + FAD (enzyme bound) <=> Fumarate + FADH2   (C) Isocitrate + NAD+ <=> Alpha-Ketoglutarate + CO2 + NADH   (D) Succinyl-CoA + Pi + GDP <=> Succinate + GTP + CoA
['(A) Alpha-Ketoglutarate + NAD+ + CoA <=> Succinyl-CoA + CO2 + NADH <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Alpha-Ketoglutarate + NAD+ + CoA <=> Succinyl-CoA + CO2 + NADH \n (B) Succinate + FAD (enzyme bound) <=> Fumarate + FADH2 \n (C) Isocitrate + NAD+ <=> Alpha-Ketoglutarate + CO2 + NADH \n (D) Succinyl-CoA + Pi + GDP <=> Succinate + GTP + CoA <> possible answers', '  A 42-year-old chronic alcoholic man was admitted to the hospital for inappropriate behavior and disturbed memory. He presents with severe retrograde memory loss, confusion, and confabulation. Neurologic examination showed horizontal nystagmus. He also has bilateral pretibial pitting edema and perioral erythema. CT studies of the brain were normal. The duty physician suspects the patient may be vitamin deficient. Which of the following reactions does the deficient vitamin mediate? <> context@']