Awoman who has blood type a positive has a daughter who is type o positive and a son who is type b negative. rh positive is a trait that shows simple dominance over rh negative and is designated by the alleles r and r, respectively. a third gene for the mn blood group has codominant alleles m and n.
which of the following is a possible partial genotype for the son?
a) ibib
b) ibia
c) ii
d) ibi
e) iaia

The answer is D) IBi

A mother has either AA or AO genotype. Since her daughter has OO genotype, the one O allele is from a father and one is from the mother.  Thus, mother must have allele O. So mother's genotype is AO.

A mother with AO genotype will pass to her son either A or O allele. Since son is type B negative, it could inherit from mother only O allele. Son's genotype is BO. This means that he inherited from the father B allele.

Talking of Rh, her son is type B negative. A negative Rh phenotype contains both recessive alleles r.
Therefore, the son genotype is BOrr. In terms of the alleles for the I locus, it can be represented as i.