A study by Solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a CCR5-delta32 mutations over 87 different countries. This mutation deletes the presence of a co-receptor (CCR5) on the outside of human T-cells (lymphocytes). Some viruses, such as the one responsible for the Black Death and Human Immunodeficiency Virus (HIV), require this receptor for attachment to host cells during the infection process. The Black Death was an epidemic that passed over northern Europe and surrounding countries during the 14th century killing nearly 60% of Europeans. This mutation is believed to have given the survivors a resistance or immunity to the Black Death. Which type of natural selection was exhibited due to the mutation? A genetic selection
B disruptive selection
C stable selection
D directional selection