The correct option is AB.
Explanation
The ABO blood group system classifies human blood based on the presence or absence of specific antigens (A and B) on the surface of Red Blood Cells (RBCs) and corresponding antibodies in the plasma. Compatibility between donor and recipient is determined by these antigens and antibodies to prevent agglutination (clumping).
Detailed Analysis:
- Blood Group AB (Universal Recipient): Individuals with blood group AB possess both Antigen A and Antigen B on their RBCs. Consequently, their plasma contains neither Anti-A nor Anti-B antibodies. Since they lack the antibodies that would react with foreign antigens, they can safely receive blood from any ABO group (A, B, AB, or O). Thus, they are known as Universal Recipients.
- Blood Group O (Universal Donor): Individuals with blood group O have neither Antigen A nor Antigen B on their RBCs. However, their plasma contains both Anti-A and Anti-B antibodies. While they can donate to any group (because their RBCs lack antigens that would trigger a reaction), they can only receive blood from group O.
- Blood Groups A and B: Group A individuals have Antigen A and Anti-B antibodies. Group B individuals have Antigen B and Anti-A antibodies. They can receive blood only from their respective groups or from Group O.
Key Takeaway:
Blood Group AB is the Universal Recipient because it lacks antibodies against A and B antigens in the plasma. Blood Group O is the Universal Donor because it lacks A and B antigens on the RBCs.