The map shows the allele frequency of sickled hemoglobin (HbS) and malaria endemicity in Africa.


Which statement best explains the relationship between HbS allele frequency and malaria endemicity in Africa?
When an area is malaria free, the HbS allele frequency is between 0 and 2.02.
When an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04.
When an area is malaria free, the HbS allele frequency is between 12.64 and 18.18.
When an area is holoendemic, the HbS allele frequency is between 0 and 0.51.