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
[{'content': 'The earliest identifiable cells of T-Cell lineage during maturation are \nSelect and explain. \nA. CD7+ Pro-T-Cells, B. CD4+ Pre-T-Cells, C. CD8+ Pro-T-Cells, D. CD8+ Pre-T-Cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]