This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Rosenthal's syndrome is due to deficiency of 
Select and explain. 
A. XI, B. VIII, C. XII, D. IX
A: XI
Answer: A: XI 
Explanation: Hemophilia C(Rosenthal syndrome) It is due to deficiency of factor XI Ref: http://en.wikipedia.org/wiki/Hemophilia_C