What is correct for blood groups O?

Options

A. No antigens but both a and b antibodies are present
B. A antigen and b antibody
C. Antigen and antibody both absent
D. A,B antigents and a,b antibodies

Explanation

To answer the question "What is correct for blood group O?", we can break down the information step by step.

### Step-by-Step Solution:

1. **Understanding Blood Groups**:
- The ABO blood group system classifies blood into four main types: A, B, AB, and O. This classification is based on the presence or absence of specific antigens on the surface of red blood cells (RBCs).

2. **Characteristics of Blood Group O**:
- Blood group O is unique because it has **no antigens** on the surface of its RBCs. This means that there are no A or B antigens present.

3. **Antibodies in Blood Group O**:
- Although blood group O has no antigens, it produces antibodies against both A and B antigens. Therefore, individuals with blood group O have **anti-A and anti-B antibodies** in their plasma.

4. **Universal Donor**:
- Due to the absence of antigens, blood group O is considered a **universal donor**. This means that people with blood group O can donate blood to individuals of any other blood group without the risk of an immune reaction.

5. **Evaluating Options**:
- Given the characteristics of blood group O, we can evaluate the provided options:
- The correct statement is that blood group O has **no antigens** but **both A and B antibodies** present. This aligns with our understanding of blood group O.
- Other options that claim the presence of A antigen, B antibody, or AB antigens are incorrect.

### Conclusion:
The correct statement for blood group O is that it has **no antigens** on the RBC surface and **both anti-A and anti-B antibodies** in the plasma.