A certain road accident patien with unknown blood group needs immediate blood transfusion. His one docter friend at once offers his blood .What was the blood group of the doner ?

Options

A. Blood group AB
B. Blood group O
C. Blood group A
D. Blood group B

Answer

To solve the question regarding the blood group of the donor who offered blood for a patient with an unknown blood group, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Blood Groups**:
- Blood groups are classified based on the presence of specific antigens on the surface of red blood cells. The main blood groups in the ABO system are A, B, AB, and O.
- Blood group A has A antigens, blood group B has B antigens, blood group AB has both A and B antigens, and blood group O has no antigens.

2. **Importance of Blood Compatibility**:
- When a blood transfusion occurs, it is crucial that the donor's blood is compatible with the recipient's blood. If the blood types are incompatible, the recipient's immune system may recognize the donor blood as foreign and mount an immune response against it.

3. **Identifying the Safe Blood Group**:
- Since the patient’s blood group is unknown, the safest option for a blood transfusion is to use blood from a donor with blood group O. This is because blood group O has no A or B antigens, making it universally acceptable for transfusions.

4. **Conclusion**:
- Therefore, the blood group of the donor who offered his blood to the patient must be blood group O.

### Final Answer:
The blood group of the donor is **O**.

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