Context: In a group of rock pocket mice, some individuals have dark fur and others have light fur. In this group, the gene for the fur color trait has two alleles. The allele for light fur (f) is recessive to the allele for dark fur (F).
Alvin is a rock pocket mouse from this group. Alvin has the homozygous genotype ff for the fur color gene.
Based on this information, what is Alvin's phenotype for the fur color trait?
A. light fur
B. dark fur
From the given choices, choose the correct answer and respond with the letter of that choice.

A