Concept:Blood transfusion compatibility depends on the recipient’s antibodies reacting against the donor’s blood group antigens.
Explanation:Patient X has genotype
AO, so his blood group phenotype is
A.
Patient Y has genotype
AB, so his blood group phenotype is
AB.
A person with group
A can safely receive blood from donors with group
A or group
O.
Group
A blood contains anti-B antibodies, so receiving group
B blood causes a dangerous reaction.
This explains why patient X showed difficulty in breathing.
A person with group
AB has no anti-A or anti-B antibodies, so group
AB can receive blood from all groups safely.
Since patient Y showed no negative reaction, the donor blood must contain the
B antigen but not harm
AB.
The donor genotype that produces group
B blood is
BO.
Answer:C.
BO