A neonate with TORCH syndrome develops respiratory insufficiency and expires. A lobule of the thymus is examined at autopsy (shown in the image). What crucial T-cell maturation step takes place within the region indicated by the circle? 

1. (A)  Negative selection for foreign antigen recognition

2. (B)  Negative selection for MHC recognition

3. (C)  Negative selection for self-antigen recognition

4. (D)  Positive selection for foreign antigen recognition 

Practice more than 1000 long stem questions in the Revision series and come out victorious. Enrol to Revision series to get access. Subscribe here today