A 22-year-old woman comes to the physician for a follow-up examination. One year ago, she was diagnosed with a pulmonary embolism. Two years ago, she delivered a female stillborn at 23 weeks' gestation. Physical examination today shows no abnormalities. Laboratory studies show a platelet count of 250,000/mm3, a prothrombin time within the reference range, and an increased partial thromboplastin time.
A. Antiphospholipid antibody syndrome
B. Factor V Leiden mutation
C. Increased factor VIII (antihemophilic factor) concentration
D. Protein C deficiency
E. Prothrombin G20210A mutation