<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 12-year-old boy, otherwise healthy, presents with frequent nosebleeds and lower extremity bruising. His mother reports that his symptoms started about 2 weeks ago and have not improved. The patient received the Tdap vaccine 2 weeks ago. He has no current medications. The review of systems is significant for the patient having a stomach ache after winning a hamburger eating competition 2 weeks ago. The vital signs include: temperature 37.0C 98.6F, blood pressure 11075 mm Hg, pulse 95min, respirations 15min, and oxygen saturation 99 on room air. On physical exam, the patient is alert and cooperative. The cardiac exam is normal. The lungs are clear to auscultation bilaterally. The lower extremities findings are shown in the image. Laboratory results are pending. Which of the following best describes the pathogenesis of this patients condition?? A: Shiga-toxin mediated damage to vascular endothelium, resulting in microthrombi formation, B: Deficiency of ADAMTS13, C: IgG autoantibodies against platelet glycoproteins, D: Systemic activation of clotting cascade resulting in platelet and coagulation factor consumption, E: Deposition of IgA immune complexes,  <response>: Based on the information provided in the question stem, this appears to be a case of immune thrombocytopenic purpura ITP. The key findings are a 12-year-old boy with recent onset of nosebleeds and bruising, low platelets suggested by the leg petechiae, and a history of receiving the Tdap vaccine 2 weeks prior. This time course suggests an immune-mediated reaction to the vaccine as the likely pathogenesis. Shiga toxin and IgA deposition can be ruled out based on the clinical history. ADAMTS13 deficiency and systemic coagulation activation are less likely in an otherwise healthy child. Therefore, the answer is most likely autoantibodies against platelet glycoproteins, which is the underlying mechanism in ITP.C: IgG autoantibodies against platelet glycoproteins 