This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Anatomy
A 30-year-old male presented with complaints of chapping and fissuring of the lips, a sore red tongue and oily, scaly skin rashes on scrotum, vulva and philtrum. Lab findings reveal increased activity of glutathione reductase activity in the RBCs. Which of the following enzymes use the above deficient vitamin as coenzyme: - 
Select and explain. 
A. Alpha-ketoglutarate dehydrogenase, B. Succinate dehydrogenase, C. Xanthine dehydrogenase, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: This is a case of Riboflavin deficiency. This presents as cheilosis, red tongue and oily and scaly skin. Enzymes using FAD as coenzyme: - Alpha-ketoglutarate dehydrogenase Succinate dehydrogenase Xanthine dehydrogenase