A donor having blood group AB cannot donate his/her blood to the recipient who has blood group O because

Correct option is A

Correct Answer: A. Donor has both the antigens

• Blood group AB individuals have both A and B antigens on the surface of their red blood cells.

• Blood group O individuals have no A or B antigens but have anti-A and anti-B antibodies in their plasma.

• When AB blood is transfused into an O recipient, the anti-A and anti-B antibodies in the O recipient’s plasma will attack the A and B antigens on the donor's red blood cells — causing a severe transfusion reaction.

• Universal Donor: Blood group O negative — because it has no antigens and thus doesn't trigger an immune response.

• Universal Recipient: Blood group AB positive — because it lacks anti-A and anti-B antibodies, so it can accept any blood type.

• Blood Compatibility Rule: Transfusion must match antigens of donor with absence of corresponding antibodies in recipient.

• Antigen vs. Antibody:

  • Antigen: On RBC surface (A or B)

  • Antibody: In plasma (anti-A or anti-B)