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
The deficiency of coagulation factor IX is associated with: 
Select and explain. 
A. Haemophilia A, B. Haemophilia B, C. Henoch-schonlein purpura, D. Sickle cell anaemia
B: Haemophilia B
Answer: B: Haemophilia B 
Explanation: Genetic conditions dealt with by clinicians in other specialties: