Answer
b.
Work Step by Step
If Edward is heterozygous for the sickle cell trait, then his genotype is Ss. This means that each parent gave a different allele, or form of the gene, to Edward. Because Edward inherited one chromosome from the homologous pair that carries this trait from each parent, he received one dominant allele (S) on one of the homologous chromosomes and one recessive allele (s) from the other.
