Which of the following reasons is mainly responsible for graft rejection in transplantation of organs?

Graft rejection in organ transplantation is mainly due to a cell-mediated immune response. In this response, the
Recipient’s immune system recognizes the transplanted organ as foreign and launches an attack against it, primarily involving T cells. These T cells recognize and attack the donor’s tissue leading to the rejection of the transplanted organ. Effective immunosuppressive medications are used to manage this immune response and prevent organ rejection after transplantation.
(1) Inability of recipient to differentiate between ‘self’ and ‘non-self’ tissues/ cells leads to autoimmune response in which the immune system attacks its own tissues/cells.
(2) Humoral immune response, involving antibodies, can also play a role in graft rejection, but the primary mechanism is cell-mediated immunity.
(3) An auto-immune response occurs when the immune system attacks the body’s own tissues, mistaking them for foreign substances. Graft rejection is an alloimmune response, where the immune system of the recipient reacts against the tissues of a genetically different individual (the donor).