Context: In a group of rainbow trout, some individuals have a greenish-brown body and others have a blue body. In this group, the gene for the body color trait has two alleles. The allele for a blue body (b) is recessive to the allele for a greenish-brown body (B).
A certain rainbow trout from this group has the heterozygous genotype Bb for the body color gene.
Based on this information, what is this trout's phenotype for the body color trait?
A. a greenish-brown body
B. a blue body
Identify the correct option from the choices provided and respond with the letter of the correct option.

A