You Are Studying the DNA of a Person Who You

 You are studying the DNA of a person who you know has two defective copies of the gene that encodes phenylalanine hydroxylase. You are surprised to find that this person also carries two defective copies of the gene for homogentisic acid oxidase. What disease symptoms will this person exhibit? (Assume pathway intermediates are not available from sources outside the phenylalanine breakdown pathway.)

A) This person will exhibit symptoms of alkaptonuria.
B) This person will exhibit symptoms of tyrosinosis.
C) This person will exhibit symptoms of phenylketonuria.
D) This person will exhibit symptoms of alkaptonuria and phenylketonuria.
E) This person will be phenotypically normal.