Which Scenario Supports Garrod's One-Gene, One-Enzyme Hypothesis of Metabolic Disease

Which scenario supports Garrod's one-gene, one-enzyme hypothesis of metabolic disease causation?

A) The disease PKU is due to the failure to produce a functional variant of an enzyme.
B) A blood disease is due to a recessive allele in one of two genes.
C) A neurological disease is due to a dominant allele in a single gene.
D) Multiple genes contribute to the likelihood that a person will develop coronary heart disease.
E) ATCase, which catalyzes the first step in the pyrimidine biosynthetic pathway, is a 12-subunit complex constructed of catalytic and regulatory chains.