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
[{'content': 'Memory T Cells can be identified by using the following marker \nSelect and explain. \nA. CD 45 RA, B. CD 45 RB, C. CD 45 RC, D. CD 45 RO', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]