A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin, Bob), even though Jane has previously given blood for one of Bob's needed transfusions, because ________.

A) Jane's blood type is a match to Bob's but her MHC proteins are not.
B) A blood type match is less stringent than a match required for transplant because blood is more tolerant of change.
C) For each gene, there is only one blood allele but many tissue alleles.
D) Jane's class II genes are not expressed in bone marrow.
E) Bob's immune response has been made inadequate before he receives the transplant.

Even though two people blood group or type might be a match, MHC proteins are not dependent on blood group and it is important that if you want to perform a bone marrow transplant, then the bone marrow of the person must match yours as much as possible. Hence it is possible for Jane to have Bob some of her blood, but a test must be done to ascertain a match in the case of a bone marrow transplant.