question: Q:A 35-year-old woman comes to the physician because of a 3-month history of worsening fatigue. She has difficulty concentrating at work despite sleeping well most nights. Three years ago, she was diagnosed with Crohn disease. She has about 7 non-bloody, mildly painful bowel movements daily. Her current medications include 5-aminosalicylic acid and topical budesonide. She does not smoke or drink alcohol. She appears pale. Her temperature is 37.9°C (100.2°F), pulse is 92/min, and blood pressure is 110/65 mmHg. The abdomen is diffusely tender to palpation, with no guarding. Laboratory results show:
  Hemoglobin 10.5 g/dL
  Mean corpuscular volume 83 μm3
  Reticulocytes 0.2 %
  Platelets 189,000/mm3
  Serum
  Iron 21 μg/dL
  Total iron binding capacity 176 μg/dL (N=240–450)
  A blood smear shows anisocytosis. Which of the following is the most appropriate next step in treatment?"? 
  {'A': 'Oral prednisone therapy', 'B': 'Subcutaneous erythropoietin injection', 'C': 'Red blood cell transfusion', 'D': 'Intravenous metronidazole therapy', 'E': 'Oral vitamin B12 supplementation'},