You are answering a USMLE-style medical question. Question: A 47-year-old man presents to the emergency department with fever, fatigue, and loss of appetite for 1 week, followed by right shoulder pain, generalized abdominal pain, and paroxysmal cough. He has had diabetes mellitus for 15 years, for which he takes metformin and gliclazide. His vital signs include a temperature of 38.3°C (101.0°F), pulse of 85/min, and blood pressure of 110/70 mm Hg. On examination, he is ill-appearing, and he has a tender liver edge that is palpable approx. 2 cm below the right costal margin. Percussion and movement worsens the pain. Abdominal ultrasonography is shown. Stool is negative for Entamoeba histolytica antigen. Which of the following is the best initial step in management of this patient condition? Options: A) Metronidazole and paromomycin B) Cholecystectomy C) Antibiotics and drainage D) Endoscopic retrograde cholangiopancreatography (ERCP) Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.