You are answering a USMLE-style medical question. Question: A 65-year-old man comes to the physician because of a 1-week history of yellowish discoloration of his skin and generalized pruritus. Examination shows jaundice of the skin and scleral icterus. Urinalysis shows an elevated concentration of bilirubin and a low concentration of urobilinogen. Which of the following is the most likely underlying cause of these findings? Options: A) Absent UDP-glucuronosyltransferase activity B) Increased hemoglobin breakdown C) Increased intestinal bilirubin reabsorption D) Defective hepatic bile excretion Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.