You are answering a USMLE-style medical question. Question: A 24-year-old woman comes to the physician because of 1-day history of nausea and weakness. She has no history of serious illness. She is sexually active with 2 male partners and uses an oral contraceptive; she uses condoms inconsistently. Her last menstrual period was 4 days ago. Her temperature is 37.8°C (100°F), pulse is 88/min, respirations are 18/min, and blood pressure is 115/70 mm Hg. Physical examination shows right costovertebral angle tenderness. The abdomen is soft and nontender. Cardiopulmonary examination shows no abnormalities. Laboratory studies show: Hemoglobin 14 g/dL Leukocyte count 13,000/mm3 Platelet count 250,000/mm3 Serum Urea nitrogen 18 mg/dL Creatinine 0.8 mg/dL Glucose 95 mg/dL C-reactive protein 16.4 mg/L (N=0.08–3.1) Which of the following is the most appropriate next step in management?" Options: A) Urinalysis B) Cervical swab C) Blood culture D) CT scan of the abdomen " Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.