This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'Cause of ITP is \nSelect and explain. \nA. Vasculitis, B. Antibody to vascular epithelium, C. Antibody to platelets, D. Antibody to clotting factors', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]