The correct response is:
The characteristic (blue eyes) is carried in a recessive gene.
Brown eyes are typically considered a dominant trait, while blue eyes are a recessive trait. For Tim to have blue eyes, both of his parents must carry the recessive gene, even if they do not express it themselves. This means that each parent can have the genotype (Bb), where B is the brown eye allele (dominant) and b is the blue eye allele (recessive). If Tim inherits the recessive allele (b) from both parents (bb), he will have blue eyes.