Why Did Dr

Why did Dr. Allison think there might be a relationship between sickle cell and malaria?

A) In areas where sickle cell was common, malaria was also common.
B) People with malaria were also likely to have sickle cell disease.
C) Mosquitoes are associated with both diseases.
D) In areas where sickle cell was common, malaria was uncommon.
E) People weakened by malaria were more likely to develop sickle cell disease.