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: Medicine
[{'content': 'The marker for B lymphocyte is? \nSelect and explain. \nA. CD 19, B. CD 68, C. CD 34, D. CD 4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (CD 19) : CD 19 is a marker for B lymphocytes. Markers for various lineage Lymphoid lineage B Lineage T Lineage CD79a CD3 (m/cyt) cyt IgM Anti-TCR cilfl cyt CD22 Anti-TCR y/c5 CD19 CD2 CD10 CD5 CD20 CD8 CD10 TdT TdTT CD24 CD7 CD1a Myeloid lineage Myeloid Lineage Anti-MPO (monoclonal) MPO cytochemistry CD117 CD13 CD33 CD65s Anti-MPO (polyclonal) CD14 CD15 CD64', 'role': 'assistant'}]