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: Pathology
[{'content': 'PTT is prolonged in all except \nSelect and explain. \nA. ITP, B. Christmas disease, C. Hemophilia A, D. Hemophilia B', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In ITP\n\nBleeding time : prolonged\nPT and PTT are normal\nClotting time : Normal', 'role': 'assistant'}]