A 28-year-old woman presents to the ED because of abdominal pain that started 2 h ago. She has nausea and vomited twice in the last hour. She reports that the pain is predominantly in the right lower quadrant. On physical exam, her blood pressure is 120/ 60 mmHg, heart rate is 100/ min, and she is afebrile. She is very tender in the RLQ on palpation at McBurney's point and has pain on passive extension of the right hip. Her WBC is 14 × 103/ μL (normal 4.1- 10.9 × 103/ μL), hemoglobin is 12 g/ dL (12- 15.2 g/ dL), hematocrit is 36 % (37- 46%), and platelet count is 250,000 (140- 450,000). Her urinalysis shows 1 + white blood cells. Which of the following is the best next step in management?

(A) Admit for observation

(B) CT scan of the abdomen

(C) Laparoscopic appendectomy

(D) B-hCG

(E) Broad-spectrum antibiotics