A version of a gene is called a(n)
O allele.
O autosome.
O karyotype
O phenotype.

allele

Explanation:

An allele can be defined as a variant of a gene localized at the same locus or chromosome position. These gene variants may encode the same protein (when different alleles encode the same protein sequence) or different protein variants (when nucleotidic differences encode distinct protein sequences). It is important to note that the diploid organisms (like humans) have two alleles for each gene, which are localized on homologous chromosomes.

i think the answer would be d