The amount of enzyme activity in a cell that is homozygous for a mutant allele is 400 units. The ...

The amount of enzyme activity in a cell that is homozygous for a mutant allele is 400 units. The amount of enzyme activity in a cell homozygous for the WT allele is 200 units. The amount of enzyme activity in a heterozygote is 300 units.
 
  What is the dominance relationship between the WT and mutant allele for the phenotype of amount of enzyme per cell? A) The WT allele is dominant.
  B) The mutant allele is dominant.
  C) The WT and mutant alleles are codominant.
  D) The WT and mutant alleles show incomplete dominance.
  E) It is impossible to determine from the information given.