A 40-year-old, formerly obese female presents to her physician. She was very proud of having lost 80 lb during the previous 2 years, but has now noticed that her 'hair is falling out.' On questioning, she reports having followed a strict, fat-free diet. Her alopecia is probably related to a deficiency of which of the following vitamins (referring to the diagram of hexose monophosphate shunt showing vitamins A, C, D, E, K)?

1. A)AGABARITO
2. B)C
3. C)D
4. D)E
5. E)K