The process in which recipient body rejects the transplanted organ is called a allograft rejection or transplantation rejection.
A transplanted organ contains Major histocompatibility complex (MHC) antigens which are required to be accepted by the recipient's body to function properly but T cells in recipient's body become alloreactive and recognize MHC antigens (donor-derived antigens) as foreign and starts making antibodies against it. Which means the recipient's body is rejecting the transplanted organ.
Hence, the correct answer is "Major histocompatibility complex (MHC) antigens".
Source credibility is very important. If there isn't any other information that proves or disproves your source or double checks it, its not typically "credible"
Most autotrophs use a process called photosynthesis to make their food. In photosynthesis, autotrophs use energy from the sun to convert water from the soil and carbon dioxide from the air into a nutrient called glucose. Glucose is a type of sugar. The glucose gives plants energy