Answer: B. to see Plasmodium populations that counter the HLA-B53 allele.
Explanation: An evolutionary arm race is a process whereby two gene exist together( Co- evolve) and they develop adaptation against each other. Hence, plasmodium develops mutation that prevent the protective effect HLA-B53 allele on them such that the mutant can adapt with the presence of HLA B53. This could be through virulence which is the production of malignant or highly infectious strains of plasmodium or by not being detected by the immune system.