select the set of parents that cannot produce child with blood group 'O'

Options

A. `I^Ai × I^Ai`
B. `I^Bi × I^AI^A`
C. `ii × I^Ai`
D. `I^BI^B × I^AI^B

Answer

To solve the question of which set of parents cannot produce a child with blood group 'O', we need to understand the genetics of blood groups. Blood groups are determined by the presence of specific alleles: A, B, and O.

### Step-by-Step Solution:

1. **Understand Blood Group Genetics**:
- Blood group A can be represented as either AA (homozygous) or AO (heterozygous).
- Blood group B can be represented as either BB (homozygous) or BO (heterozygous).
- Blood group AB is represented as AB (both alleles are present).
- Blood group O is represented as OO (homozygous recessive).

2. **Identify Possible Combinations**:
- For a child to have blood group O (OO), both parents must contribute an O allele.
- Therefore, at least one parent must have blood group O, or one parent must have a genotype that includes an O allele (AO or BO).

3. **Evaluate Each Parent Set**:
- **Set 1**: Parent A (AA) and Parent B (BB)
- Possible offspring: AB (from A and B), but no O allele is present. Thus, they cannot produce a child with blood group O.
- **Set 2**: Parent A (AO) and Parent B (BO)
- Possible offspring: A, B, AB, and O. They can produce a child with blood group O.
- **Set 3**: Parent A (AO) and Parent B (OO)
- Possible offspring: A and O. They can produce a child with blood group O.
- **Set 4**: Parent A (AB) and Parent B (AB)
- Possible offspring: A, B, and AB. They cannot produce a child with blood group O.

4. **Conclusion**:
- The sets of parents that cannot produce a child with blood group O are:
- Set 1: AA and BB
- Set 4: AB and AB

### Final Answer:
The sets of parents that cannot produce a child with blood group 'O' are:
1. Parent A (AA) and Parent B (BB)
2. Parent A (AB) and Parent B (AB)