26.What is a possible reason for an organ transplant rejection in identical twins, given their genetic similarity? (A) Differences in blood type between the twins, as blood type compatibility is crucial for successful organ transplantation. (B) Minor genetic mutations that occurred post-zygotically, leading to slight genetic differences between the twins. (C) The presence of different sets of major histocompatbili complex (MHC) molecules, leading to immune recognition and rejection﹒ (D) Psychological stress in the recipient twin, which can indirectly trigger an immune response against the transplanted organ﹒ (E) Environmental factors leading to different gut microbiota in the twins, which can influence immune responses and organ compatibility.