A 12-year-old girl has recurrent gingival bleeding and heavy menses. Her platelet count, PT, and PTT are normal, but bleeding time is prolonged. Platelet aggregation studies show absent aggregation in response to ADP, collagen, and epinephrine, with normal ristocetin response. Which of the following is the most likely cause of her disease?

1. A)Deficiency of vitamin K
2. B)Deficiency of GpIb
3. C)Deficiency of ADAMTS13
4. D)Deficiency of GpIIb/IIIaGABARITO
5. E)Deficiency of factor IX