State which of these statements about blood group (ABO system and Rh system taken together ) is correct.

Options

A. The blood group having all the possible antigens present in these two systems is the universal recipient
B. The blood group considered as the universal donor is also the commonest Blood group in humans
C. The blood group considered as the universal recipient is also the rarest blood group in humans
D. The blood group having no antibodies against any of the antigens in these two system is the universal donor

Answer

To determine which statement about blood groups (ABO system and Rh system) is correct, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Blood Groups**:
- The ABO blood group system consists of four main blood types: A, B, AB, and O.
- The Rh system includes the presence (+) or absence (-) of the Rh factor (D antigen).

2. **Identifying the Universal Recipient**:
- The universal recipient blood group is AB.
- Individuals with AB blood type have both A and B antigens on their red blood cells and do not have antibodies against A or B antigens.
- This means they can receive blood from any ABO type without risk of agglutination.

3. **Identifying the Universal Donor**:
- The universal donor blood group is O.
- Individuals with type O blood have no A or B antigens on their red blood cells, which means their blood can be given to any ABO type without causing an immune reaction.

4. **Analyzing Each Statement**:
- **Option A**: "The blood group having all the possible antigens present in these two systems is the universal recipient."
- This statement is correct because AB blood group has both A and B antigens.

- **Option B**: "The blood group considered as the universal donor is also the commonest blood group in humans."
- This statement is incorrect. While O is the universal donor, it is also one of the most common blood groups, but it is not the only one.

- **Option C**: "The blood group considered as universal recipient is also the rarest blood group in humans."
- This statement is incorrect. AB is not the rarest blood group; it is less common than O but not the rarest.

- **Option D**: "The blood group having no antibodies against any of the antigens in these two systems is the universal donor."
- This statement is incorrect. The universal donor is type O, which has antibodies against A and B antigens.

5. **Conclusion**:
- The correct statement is **Option A**: "The blood group having all the possible antigens present in these two systems is the universal recipient."