When Persons Are Heterozygous for the Sickle Cell Trait, They

When persons are heterozygous for the sickle cell trait, they are

A) carriers with one normal and one abnormal gene.
B) open to a range of serious medical problems.
C) sufferers open to long bouts of illness and often death in childhood.
D) recipients of a mismatched chromosome pair at the 21st level.
E) prone to ruptured blood cells and serious heart damage.