Which Statement Concerning Phenylketonuria (PKU) Is True

Multiple Choice

Which statement concerning phenylketonuria (PKU) is true?

A) It manifests due to excessive intake of fatty foods.
B) It is interesting to researchers because it does not require an interaction of genes and environment to be expressed.
C) Left untreated, it can cause intellectual disability.
D) For those affected, dietary restrictions are critical later in life.