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.
Peanut, a rabbit from this group, has brown fur. Peanut has two alleles for brown fur.
Based on this information, what is Peanut's phenotype for the fur color trait?
A. ff
B. brown fur
Determine the correct option from the provided choices and reply with its corresponding letter.

B