Concept:The ABO blood group system classifies blood based on the presence or absence of A and B antigens on red blood cells and corresponding antibodies in plasma. A person with blood group AB has both A and B antigens on their red cells and no anti-A or anti-B antibodies in their plasma, making them able to receive blood from any ABO group. This is why AB is called the universal acceptor (recipient).
Explanation:In human blood transfusion, compatibility is determined by the ABO and Rh systems. The four main ABO groups are A, B, AB, and O. Their antigen–antibody characteristics and donor compatibility are summarised below:
As shown in the table, blood group AB has no antibodies (nil) and both A and B antigens. Therefore, when a person with AB blood receives blood from any ABO group (A, B, AB, or O), their plasma will not react against the donated red cells. This makes AB the universal acceptor. (Including the Rh factor, AB positive is considered the universal recipient because it can receive both Rh‑positive and Rh‑negative blood.)
Answer:C. AB