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
In which of the following condition PAS test has block positivity 
Select and explain. 
A. ALL L1, B. AML, C. CML, D. Hodgkins lymphoma
A: ALL L1
Answer: A: ALL L1 
Explanation: Periodic acid - schiff (PAS) stain is useful for the diagnosis of ALLs and erythroid and megakoryocytic (M6 and M7) type of acute myeloid leukemia.
Block positivity in lymphoblast is oberved in ALL L1 cores.