You are answering a USMLE-style medical question. Question: A one-week-old boy presents with yellow sclerae, severe lethargy, and decreased muscle tone. His mother notes that the symptoms started shortly after birth and have been progressively worsening. The patient is breast fed and takes no medications. His labs are within normal limits with the exception of his liver function tests as follows: ALT: 8 U/ L AST: 10 U/L Alkaline phosphatase: 50 U/L Albumin: 3.7 g/dL Total protein: 6.7 g/dL Bilirubin, total: 29.4 mg/dL Bilirubin, unconjugated: 29.2 mg/dL Bilirubin, conjugated: 0.2 mg/dL The boy is taken immediately for treatment. What is the most likely underlying cause of his condition? Options: A) Absence of UDP-glucuronosyltransferase-1A1 B) Alteration in the ankyrin protein C) Reduction in UDP-glucuronosyltransferase-1A1 activity D) Deficiency in glucocerebrosidase Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.