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
[{'content': 'Which of the following is the most common manifestation of hemophilla? \nSelect and explain. \nA. Hemoptysis, B. Hemarthrosis, C. Hematemesis, D. Mucosal bleeding', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref. Robbins Pathology. 9th edition. Page. 665', 'role': 'assistant'}]