Which of the following do you expect if an individual is heterozygous for the sickle-cell trait? see concept

A. they will not develop sickle-cell disease
B. they will show some symptoms of the disease because the allele that causes sickle-cell disease is not really recessive
C. they will be more apt to acquire a serious case of malaria
D. they will have full-blown sickle-cell disease because the allele is dominant
E. none of the listed choices are correct