The parent's genotypes are

and

respectively. When crossed together, all possible genotypes can be expressed. 1/4 AB blood, 1/4 A blood (heterozygous), 1/4 B blood (heterozygous) and 1/4 O blood. A Punnett square has been uploaded to support this.
Answer:
Phenotype
Explanation:
"only four phenotypes result from the six possible ABO genotypes. How does this happen? To understand why this occurs, first note that the A and B alleles code for proteins that exist on the surface of red blood cells; in contrast, the third allele, O, codes for no protein."
Sorry if im wrong