A 14-year-old girl presents to her primary care physician with a 6-month history of progressively heavy menstrual periods requiring frequent pad changes and soaking through overnight. She also reports spontaneous bleeding from her gums when brushing her teeth. Her parents deny any family history of bleeding disorders. Vital signs are within normal limits. Laboratory evaluation reveals: Platelet count 245,000/μL, PT 12 seconds (normal), aPTT 34 seconds (normal), fibrinogen 320 mg/dL (normal). Bleeding time is prolonged at 11 minutes. Platelet aggregation studies show normal platelet aggregation in response to ristocetin but absent aggregation in response to adenosine diphosphate (ADP), epinephrine, and collagen. Which of the following is the most likely defect underlying this patient's clinical presentation?

1. A)Deficiency of P2Y12 adenosine diphosphate receptor
2. B)Absence of glycoprotein Ib-IX-V complex
3. C)Deficiency of glycoprotein IIb/IIIa integrinGABARITO
4. D)Impaired von Willebrand factor synthesis
5. E)Thromboxane A2 synthase deficiency