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: Microbiology
The earliest identifiable cells of T-Cell lineage during maturation are 
Select and explain. 
A. CD7+ Pro-T-Cells, B. CD4+ Pre-T-Cells, C. CD8+ Pro-T-Cells, D. CD8+ Pre-T-Cells
A: CD7+ Pro-T-Cells
Answer: A: CD7+ Pro-T-Cells 
Explanation: None