If a Patient Received a Kidney Transplant That Was Matched

If a patient received a kidney transplant that was matched well across each of the major histocompatibility complex (MHC) molecules, but they stopped taking their anti-rejection drugs, what would happen and why?

A) Nothing; the transplant is matched, so the patient doesn't need the drugs to prevent rejection. The new organ should be seen by the recipient's immune system as "self."
B) The organ will be rejected very quickly, as allografts (tissue from the same species, but a different individual) are seen by the recipient's immune system as "foreign," and are quickly attacked.
C) The organ will be rejected, but it will be a gradual process since it was matched well. There are a number of other proteins that cannot be matched between donors, so the graft will still be viewed as "foreign" by the recipient's immune system, and will still be attacked and rejected.
D) Nothing; since the transplant was accepted for so long with the anti-rejection drugs, the person's immune system has had the time to become accustomed to it and now views the graft as "self." It will not be attacked.
E) Nothing. The anti-rejection drugs are not really necessary once the patient's surgery wounds have healed. At the time their immune system returns to normal, so the new organ will not be rejected.