Alleles for the A and B blood cell antigens are codominant. The condition where no antigens are present on the blood cells (type O blood) is a recessive trait. Which set of parents can most likely produce a child with
type O blood

This question lacks options, the options are:

A. one parent with type AB blood, and the other parent with type A blood

B. one parent with type AB blood and the other parent with type O blood

C. one parent with heterozygous type A blood, and the other parent with type O blood

D. one parent with homzygous type A blood, and the other parent with homzygous type B blood

The answer is C. One parent with heterozygous type A blood, and the other parent with type O blood

Explanation:

Blood type in humans is controlled by a gene with multiple alleles. The alleles for the A (iA) and B (iB) blood types are codominant but dominant over the O type (i). This means that an individual can only have blood O type if the genotype is (ii).

According to this question, the set of parents that can most likely produce a child with type O blood is: one parent with heterozygous type A (iAi) blood, and the other parent with type O (ii) blood. This is because the parent with type A blood will release gamete will "i" allele while the parent with type O will also release gamete will "i" allele, hence, an individual with ii (type O) forms.