This is the genotype of blood group A

The correct option is Iᴬ Iᴬ or Iᴬ Iᴼ.

In the ABO blood group system, the blood types are determined by three different alleles of a single gene: ^IA, ^IB, and ^IO (often written as i).

The alleles ^IA and ^IB are co-dominant with each other, meaning both will be expressed if present together (resulting in blood group AB). However, both ^IA and ^IB are completely dominant over the recessive ^IO allele.

For an individual to have blood group A, they must express the A antigen. Due to the dominance relationships, this phenotype can arise from two distinct genetic combinations:
1. Homozygous genotype (Iᴬ Iᴬ): The individual inherits the dominant ^IA allele from both parents.
2. Heterozygous genotype (Iᴬ Iᴼ): The individual inherits the dominant ^IA allele from one parent and the recessive ^IO allele from the other. Because ^IA is dominant, the recessive ^IO allele is masked, and the individual's blood type is A.

Therefore, the genotype for blood group A can be either Iᴬ Iᴬ or Iᴬ Iᴼ.