The right answer is B) heterozygous.
Sickle cell disease is a genetic, inherited disease affecting red blood cells, in which a child can be ill only if both parents are transmitters (at least heterozygous, carrier of the trait), ie asymptomatic carriers of the gene for sickle cell disease. It is a hereditary autosomal recessive disease, that is, it affects girls as well as boys, and only manifests itself when one carries two genes of the disease (homozygous). This disease is genetic and therefore not contagious.
