Final answer:
The plasma membrane proteins that identify cells as self or non-self are antigens, which are typically glycoproteins. Antibodies recognize and bind to these antigens to facilitate an immune response.
Step-by-step explanation:
The proteins in the plasma membrane that identify a cell as part of the same individual or as foreign are B) Antigens. These antigenic molecules are often glycoproteins, and they are essential for immune recognition. Specifically, antibodies, which are also known as immunoglobulins, are produced by the immune system to recognize and bind to these antigens, tagging them for destruction or neutralization if identified as foreign. All nucleated cells in the body present MHC I (Major Histocompatibility Complex class I) molecules that display antigens to T cells, indicating self or non-self. Antigen receptors on B cells, known as B-cell receptors (BCRs), are membrane-bound proteins that recognize specific antigen epitopes and are necessary for immune responses against protein antigens, which are called T-dependent antigens.