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
Coagulation time of blood is prolonged in: 
Select and explain. 
A. Hemophilia, B. Leukemia, C. Pernicious anaemia, D. Malignant neutropenia
A: Hemophilia
Answer: A: Hemophilia 
Explanation: None