People homozygous for the sickle-cell anemia allele develop a life threatening disease, while those homozygous for the normal allele are at the highest risk of dying from malaria. carriers have some resistance to malaria, but do not develop sickle cell anemia. this is an example of

Stabilizing selection.

Explanation:

Stabilizing selection may be defined as a type of  the natural selection the mean population is stabilizes on the particular non extreme trait of a population.

The people with heterozygous condition for sickle cell trait are selected against the malaria condition. These organisms survive whereas the homozygous dominant for the normal trait and homozygous recessive dies due to malaria. Here, the heterozygous genotype individual are selected and shows the type of stabilizing natural selection.

the correct answer is b