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
PTT is prolonged in all except 
Select and explain. 
A. ITP, B. Christmas disease, C. Hemophilia A, D. Hemophilia B
A: ITP
Answer: A: ITP 
Explanation: In ITP

Bleeding time : prolonged
PT and PTT are normal
Clotting time : Normal