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
Coagulation time is prolonged in all except - 
Select and explain. 
A. Hemophilia, B. Von Willebrand's disease, C. Christmas disease, D. ITP
D: ITP
Answer: D: ITP 
Explanation: None