In amazonian giant mice, a fictional species, purple coat color is dominant over yellow coat color. two mice with the heterozygous genotype for coat color are crossed.

Purple color is expressed in 3 out of the four because the law of dominance states that only one dominant gene needs to be present to express the trait. But there is one homozygous recessive that would be yellow because the genotype has two recessive genes.
Example: AA or Aa would be dominant because the capital letter represents the dominant gene

Ithink it's c (70)