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
B cell ALL is due to which of the following? 
Select and explain. 
A. T cells, B. Immature B cells, C. Immature T cells, D. Both T and B cells
B: Immature B cells
Answer: B: Immature B cells 
Explanation: B cell ALL is due to immature B cells.