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
All the following markers are expressed on the surface of T-cells at some stage of development except: 
Select and explain. 
A. CDIa, B. PAX5, C. CD 34, D. Tdt
B: PAX5
Answer: B: PAX5 
Explanation: Answer- B. PAX5PAXS is a B-cell transcription factor, essential in normal B-cell lymphopoiesis. T-cell never express PAXS throughout its development CD-1a, CD34 and Tdt are expressed on T-cells.T cell - CDl, CD2, CD3, CD4, CD5, CD7, CD8, cCD3, lymphoid TdT.