Review Question - QID 109875

A 41-year-old man presents to his primary care provider complaining of a blistering skin rash. He was out in the sun with his family at a baseball game several days ago. Later that evening he developed a severe blistering rash on his forearms, back of his neck, and legs. He denies fevers, chills, malaise, abdominal pain, or chest pain. He denies dysuria or a change in his bowel patterns but does report that his urine has occasionally appeared brown over the past few months. His family history is notable for hemochromatosis in his father. He does not smoke or drink alcohol. On examination, he has small ruptured blisters diffusely across his forearms, back of his neck, and lower legs. This patient most likely has a condition caused by a defect in an enzyme that metabolizes which of the following compounds?