This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematopoeisis: Basic concepts, Subject name: Pathology
Which of the following surface glycoproteins is most often expressed in human hematopoietic stem cell (HSC)? 
Select and explain. 
A. CD23, B. CD30, C. CD33, D. CD34
D: CD34
Answer: D: CD34 
Explanation: Surface antigen/Marker Normal cellular distribution CD34 Pluripotent hematopoietic stem cells & progenitor cells of many lineages. CD23 Activated mature B cells CD30 Activated B cells, T cells, and monocytes; Reed-Sternberg cells and variants CD33 Myeloid progenitors and monocytes