Final answer:
The allele for green eyes is denoted by the lowercase letter 'g' and is a recessive allele, meaning the correct answer is (D) recessive.
Step-by-step explanation:
The allele for green eyes is represented by the lowercase letter 'g' which indicates that it is a recessive allele. In genetics, dominant alleles are typically represented by uppercase letters, while recessive alleles are denoted with lowercase letters. Given the genotype for green eyes as 'gg', this means that an individual must have two copies of the recessive allele to exhibit the green eye trait.
Therefore, the correct answer to describe the allele for green eyes is recessive, which corresponds to option (D). In comparison, 'B' represents the dominant allele for brown eyes, and individuals with one or two copies of this allele will exhibit brown eyes due to its dominance over the green allele.