Final answer:
Professional Antigen-Presenting Cells (PAPCs) include B cells, macrophages, and dendritic cells, which all have the special capability to present antigens to T cells to initiate an adaptive immune response, making 'All of the Above' the correct answer.
Step-by-step explanation:
The professional antigen-presenting cells (PAPC) are a group of immune cells that have the specialized ability to process and present antigens to T cells in order to trigger an adaptive immune response. The main types of professional antigen-presenting cells are B cells, macrophages, and dendritic cells.
These cells display processed antigen fragments in conjunction with class II MHC molecules on their surfaces, which are recognized by T cell receptors on T cells. Macrophages and dendritic cells can also engulf and kill pathogens through phagocytosis, whereas B cells primarily bind antigens with their immunoglobulin receptors and do not act as phagocytes. Therefore, the correct answer to the student's question is d. All of the Above.