Context: In a group of rabbits, some individuals have black fur and others have brown fur. In this group, the gene for the fur color trait has two alleles. The allele F is for black fur, and the allele f is for brown fur.
Mortimer, a rabbit from this group, has black fur. Mortimer has two alleles for black fur.
Based on this information, what is Mortimer's phenotype for the fur color trait?
A. black fur
B. FF
Answer with the option's letter from the given choices directly.

A