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
The biochemical marker of lymphocytic leukaemia is - 
Select and explain. 
A. Enolase, B. Peroxidase, C. Choline exterase, D. Periodic acid schiff
D: Periodic acid schiff
Answer: D: Periodic acid schiff 
Explanation: None