Answer:
C. They have known genotypes
Step-by-step explanation:
The genotype is the part of the genetic makeup of a cell, and therefore of any individual, which determines one of its characteristics (phenotype).
One's genotype differs subtly from one's genomic sequence, because it refers to how an individual differs or is specialized within a group of individuals or a species. So, typically, one refers to an individual's genotype with regard to a particular gene of interest and the combination of alleles the individual carries (see homozygous, heterozygous).