Why is the hypothesis that breaking a mirror cause seven years of bad luck not science? why is that the right answer?

a. the results of studying the hypothesis are repeatable
b. the results of studying the hypothesis are not biased
c. a hypothesis based on opinion cannot be tested by an experiment
d. how you break the mirror affects the results of the experiment.

Astudy 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 during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?