This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Which feature is not shared between T cells & B cells? 
Select and explain. 
A. Antigen specific receptors, B. Class I MHC receptors, C. Positive selection during development, D. All of the above
C: Positive selection during development
Answer: C: Positive selection during development 
Explanation: Selection T cells Positive selection - T cells in thymic coex are allowed to survive only if TCR has affinity for MHC molecule. If not, they are programed to die Negative selection - T cell comes to thymic medulla after being positively selected in thymic coex. In the medulla, if they have affinity for self-antigens they are eliminated. Self-tolerance B cells Receptor editing/Negative selection - when B cells recognize self-antigens in bone marrow, BCR undergo gene rearrangement