A Person Who Is Homozygous for a Mutation of the Phenylalanine

A person who is homozygous for a mutation of the phenylalanine hydroxylase gene

A) can lead a normal life if the environment is controlled.
B) cannot give blood.
C) will always develop mental retardation in early infancy.
D) will require phenylalanine supplements throughout life.
E) Two statements are correct. They can lead a normal life if the environment is controlled by taking phenylalanine supplements.