Context: This passage describes the wing type trait in fruit flies:

In a group of fruit flies, some individuals have normal wings and others have vestigial wings. In this group, the gene for the wing type trait has two alleles. The allele N is for normal wings, and the allele n is for vestigial wings.
A certain fruit fly from this group has vestigial wings. This fly has two alleles for vestigial wings.
Based on this information, what is this fruit fly's genotype for the wing type gene?
A. vestigial wings
B. nn
Answer with the option's letter from the given choices directly.
Answer: B