question: Q:A 25-year-old woman comes to the physician because of recurrent episodes of reddish discoloration of her urine. She also has a 3-month history of intermittent abdominal pain, yellowish discoloration of the skin and eyes, and fatigue. Physical examination shows pallor and scleral icterus. The spleen is not palpable. Her hemoglobin concentration is 7.8 g/dL, leukocyte count is 2,000/mm3, and platelet count is 80,000/mm3. Serum LDH and unconjugated bilirubin concentrations are elevated. Addition of a serum containing anti-human globulins to a blood sample shows no agglutination. A urine dipstick shows blood; urinalysis shows no RBCs. A CT scan of the abdomen shows a thrombus in a distal branch of the superior mesenteric vein. Which of the following is the most likely cause of this patient's condition?? 
  {'A': 'Activation and consumption of platelets and coagulation factors', 'B': 'Endothelial cell dysfunction from bacterial toxin production', 'C': 'Absence of protective factors against destruction by complement', 'D': 'Formation of IgG antibodies against glycoprotein IIb/IIIa', 'E': 'Replacement of a single amino acid in a β-globin chain\n"'},