A 27-year-old woman with a 5-year history of ulcerative colitis presents to the emergency department with a 3-day history of crampy abdominal pain, bloody diarrhea 8-10 times daily, and fever to 38.9°C (102°F). She reports increased urgency and tenesmus. On examination, she appears ill, with diffuse abdominal tenderness and rebound tenderness. Vital signs show heart rate 110 bpm, blood pressure 95/58 mmHg, and respiratory rate 22/min. Laboratory studies reveal hemoglobin 9.2 g/dL, WBC 14,500/μL, albumin 2.8 g/dL, and CRP 8.2 mg/dL. Abdominal radiograph demonstrates a dilated colon with a maximum diameter of 6.5 cm. Stool studies are negative for Clostridioides difficile and infectious pathogens. Which of the following is the most appropriate next step in management?

1. A)Initiate infliximab therapy and transition to oral 5-aminosalicylates
2. B)Perform urgent colonoscopy with biopsy to confirm disease severity
3. C)Administer broad-spectrum antibiotics and begin mesalamine therapy
4. D)Begin high-dose intravenous corticosteroids and consult surgeryGABARITO
5. E)Start oral corticosteroids with antispasmodic agents for symptomatic relief