This problem refers to the MN  and ABO loci mentioned in class. It also refers to the Rh locus, which is responsible for the positive/negative part of the blood type. The Rh+ allele is dominant to the Rh- allele at this locus. Select all couples who could be the parents of a child with phenotype M, A+ based on the phenotypes at these three loci. If none of these couples could be the parents of this child, select “None of These”.