Which of the Following Best Describes the Relation Between Sickle

Which of the following best describes the relation between sickle cell anemia and malaria?

A) An overabundance of hemoglobin caused by malaria counteracts sickle cell anemia.
B) People who only have one allele for sickle cell anemia are poor hosts for malaria and therefore more likely to survive it.
C) The two diseases do not co-occur.
D) The two diseases can co-occur but not in the same geographic region.
E) The malaria parasite's primary niche is inside people with sickle cell anemia.