You are answering a USMLE-style medical question. Question: A 30-year-old primigravid woman at 22 weeks' gestation is brought to the emergency department by her husband for lethargy, nausea, and vomiting for 4 days. This morning she became drowsy. She returned from a business trip to Sudan 3 weeks ago. She denies eating any seafood while traveling. Medications include iron supplements and a multivitamin. Her immunizations are up-to-date and she has never received blood products. Her temperature is 38.9°C (102°F), pulse is 92/min, and blood pressure is 122/76 mm Hg. She is oriented to person and place. Examination shows jaundice and mild asterixis. Pelvic examination shows a uterus consistent in size with a 22-week gestation. Laboratory studies show: Hemoglobin 11.2 g/dL Prothrombin time 18 sec (INR=2.0) Serum Total bilirubin 4.4 mg/dL Alkaline phosphatase 398 U/L AST 4,702 U/L ALT 3,551 U/L Lactate dehydrogenase 3,412 U/L Anti-nuclear antibody negative Anti-smooth muscle antibody negative Anti-CMV antibody negative Anti-EBV nuclear antigen antibody negative An ELISA for HIV is negative. Which of the following is most likely to confirm the diagnosis?" Options: A) HBsAg B) Anti-HAV IgG C) Anti-HCV IgG D) Anti-HEV IgM Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.