Blood group AB is considered as universal recipient because they can receive blood from groups

Analyze the question: The question asks why blood group AB is called the "universal recipient" and which blood groups it can receive from.

Explain the concept: Blood groups are determined by antigens on the surface of red blood cells, and by antibodies in the plasma:

| Blood group | Antigens on red cells | Antibodies in plasma | |---|---|---| | A | A | anti-B | | B | B | anti-A | | AB | A and B | none | | O | none | anti-A and anti-B |

Transfusion reactions happen when the recipient's plasma antibodies attack the donor's red cell antigens (clumping, or agglutination).

Solution:

1. Group AB has no anti-A or anti-B antibodies in its plasma.
2. So nothing in an AB person's plasma can attack A, B, AB or O red cells.
3. This means AB can safely receive blood from all four groups: A, B, AB and O.

That is why AB is called the universal recipient.

Checking the options:

• A. A and O: leaves out B and AB, so it is incomplete.
• B. B and O: leaves out A and AB, so it is incomplete.
• C. AB and O: leaves out A and B, so it is incomplete.
• D. A, B, AB and O: covers every group, so it is correct.

Exam tip: Remember the pair:

• AB = universal recipient (no antibodies, receives from all).
• O = universal donor (no antigens, gives to all).

Think of the "AB" person as having both antigens, so their body "recognises" everything and rejects nothing. (In practice, doctors still prefer matching blood groups, and Rhesus factor also matters, but for JAMB, this is the answer expected.)