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: Unknown
Which of the following is the most common manifestation of hemophilla? 
Select and explain. 
A. Hemoptysis, B. Hemarthrosis, C. Hematemesis, D. Mucosal bleeding
B: Hemarthrosis
Answer: B: Hemarthrosis 
Explanation: Ref. Robbins Pathology. 9th edition. Page. 665