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: Pathology
Marker for Hairy cell Leukemia is: 
Select and explain. 
A. CD 30, B. CD 103, C. CD1, D. CD4
B: CD 103
Answer: B: CD 103 
Explanation: CD 103