<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 38-year-old man with chronic hepatitis C comes to the physician because of a 10-day history of darkening of his skin and painless blisters. He started working as a landscaper 2 weeks ago. He drinks 2 beers every night and occasionally more on the weekends. Examination shows bullae and oozing erosions in different stages of healing on his arms, dorsal hands, and face. There are atrophic white scars and patches of hyperpigmented skin on the arms and face. This patients skin findings are most likely associated with increased concentration of which of the following?? A: Protoporphyrin, B: Porphobilinogen, C: Delta-aminolevulinic acid, D: Uroporphyrinogen III, E: Unconjugated bilirubin,  <response>: This is a question about porphyria cutanea tarda PCT, a disorder of heme biosynthesis that causes blistering skin lesions and hyperpigmentation in sun-exposed areas. The key clues in the stem are the 10-day history of skin darkening and blisters after starting a job as a landscaper, suggesting sun exposure triggered the symptoms. The patient also has a history of alcohol use, which can precipitate attacks of PCT. In PCT, there is a buildup of uroporphyrinogen and other porphyrin precursors in the skin, leading to photosensitivity. Of the answer choices, uroporphyrinogen III is the porphyrin precursor that accumulates in PCT. Protoporphyrin accumulation occurs in erythropoietic protoporphyria. Porphobilinogen and delta-aminolevulinic acid are earlier precursors in the heme synthesis pathway. Unconjugated bilirubin does not directly relate to porphyria.D: Uroporphyrinogen III 