You are answering a USMLE-style medical question. Question: A 7-year-old girl is brought to the emergency department with a 10-day history of fever and sore throat that acutely worsened over the past 2 days. Her sore throat is worse on the right side. She has difficulty swallowing and opening her mouth due to pain. She has also noticed a change in the quality of her voice over the last day. Her temperature is 38.2°C (100.8°F), pulse is 86/min, respirations are 18/min, and blood pressure is 110/75 mm Hg . Examination shows cervical lymphadenopathy. Oropharyngeal examination shows erythematous tonsils and swelling of the right tonsillar pillar. The uvula is deviated to the left. Laboratory studies show: Hemoglobin 13.0 g/dL Hematocrit 39% Leukocyte count 12,000/mm3 Platelet Count 200,000/mm3 Serum Na+ 138 mEq/L Cl- 100 mEq/L K+ 4.5 mEq/L HCO3- 24 mEq/L Urea nitrogen 14.0 mg/dL Creatinine 1.1 mg/dL Which of the following is the most appropriate next step in management?" Options: A) Intravenous dexamethasone therapy B) Incision and drainage with intravenous ampicillin-sulbactam therapy C) Needle aspiration and oral clindamycin therapy D) Intravenous ampicillin-sulbactam therapy Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.