Context: In a group of cows, some individuals have solid coloring and others have white spots. In this group, the gene for the coat pattern trait has two alleles. The allele for solid coloring (A) is dominant over the allele for white spots (a).
Boxer is a cow from this group. Boxer has the heterozygous genotype Aa for the coat pattern gene.
Based on this information, what is Boxer's phenotype for the coat pattern trait?
A. solid coloring
B. white spots
From the given choices, pick the correct answer and respond by indicating the letter of the correct option.

A