The following blood group is called universal donar

Options

A. A
B. B
C. AB
D. O

Answer

**Step-by-Step Solution:**

1. **Understanding Blood Groups**: Blood groups are classified based on the presence or absence of specific antigens on the surface of red blood cells (RBCs). The main blood groups are A, B, AB, and O.

2. **Identifying Antigens**:
- Blood group A has antigen A.
- Blood group B has antigen B.
- Blood group AB has both antigens A and B.
- Blood group O has no antigens (neither A nor B).

3. **Definition of Universal Donor**: A universal donor is a blood group that can donate blood to any other blood group without causing an immune reaction in the recipient.

4. **Analyzing Blood Group O**: Since blood group O lacks both antigen A and antigen B, it does not trigger an immune response in recipients with any blood group. Therefore, individuals with blood group O can donate blood to anyone.

5. **Conclusion**: Based on the analysis, blood group O is termed the universal donor because it can be transfused to all other blood groups without causing an allergic reaction.

6. **Final Answer**: The blood group that is called the universal donor is **blood group O**.

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